.png&w=3840&q=75)
NEET ]1[ Contd...
NEET Biology Class 12 - Organisms and Populations Ultra-Hard Question Bank
Instructions:
- Each question has four options (1), (2), (3), (4). Choose the most correct answer.
- Each correct answer carries 4 marks.
- Each wrong answer will deduct 1 marks.
- Unanswered questions will not be penalised.
1.Consider the following statements regarding the early life and academic milestones of Ramdeo Misra:
I. He was born on 26 August 1908.
II. He obtained his Ph.D. in Ecology in 1937 from Banaras Hindu
University.
III. His doctoral supervisor was the renowned Prof. W. H. Pearsall, FRS.
IV. The university
from which he received his doctorate was Leeds University in the UK. Which of the statements given
above are correct according to the NCERT Unit X introduction?
I. He was born on 26 August 1908.
II. He obtained his Ph.D. in Ecology in 1937 from Banaras Hindu
University.
III. His doctoral supervisor was the renowned Prof. W. H. Pearsall, FRS.
IV. The university
from which he received his doctorate was Leeds University in the UK. Which of the statements given
above are correct according to the NCERT Unit X introduction?
2.Given below are two statements, one is labelled as Assertion (A) and the other is labelled as Reason
(R): Assertion (A): Ramdeo Misra established the Department of Botany at the Banaras Hindu University,
Varanasi.
Reason (R): His research laid the foundations for the understanding of tropical communities
and their succession in India.
In the light of the above statements, choose the correct answer:
(R): Assertion (A): Ramdeo Misra established the Department of Botany at the Banaras Hindu University,
Varanasi.
Reason (R): His research laid the foundations for the understanding of tropical communities
and their succession in India.
In the light of the above statements, choose the correct answer:
3.Consider the following statements regarding the administrative achievements and honors of Ramdeo
Misra: I. He was honored with the Fellowships of the Indian National Science Academy and World
Academy of Arts and Science.
II. He received the prestigious Sanjay Gandhi Award in Environment and
Ecology.
III. Due to his efforts, the Government of India established the National Committee for
Environmental Planning and Coordination in 1972.
IV. His efforts directly led to the immediate
establishment of the Ministry of Environment and Forests in 1972. Which of the statements given above
are correct according to the NCERT text?
Misra: I. He was honored with the Fellowships of the Indian National Science Academy and World
Academy of Arts and Science.
II. He received the prestigious Sanjay Gandhi Award in Environment and
Ecology.
III. Due to his efforts, the Government of India established the National Committee for
Environmental Planning and Coordination in 1972.
IV. His efforts directly led to the immediate
establishment of the Ministry of Environment and Forests in 1972. Which of the statements given above
are correct according to the NCERT text?
4.Given below are two statements, one is labelled as Assertion (A) and the other is labelled as Reason
(R): Assertion (A): Ramdeo Misra is widely revered as the Father of Ecology in India.
Reason (R): Under
his direct supervision, over 50 scholars obtained their Ph.D. degrees, and he formulated the first
postgraduate course in ecology in India.
In the light of the above statements, choose the correct answer:
(R): Assertion (A): Ramdeo Misra is widely revered as the Father of Ecology in India.
Reason (R): Under
his direct supervision, over 50 scholars obtained their Ph.D. degrees, and he formulated the first
postgraduate course in ecology in India.
In the light of the above statements, choose the correct answer:
5.According to the introductory section of Unit X (Ecology), which of the following statements are
correct?
I. Biology is presented either as botany, zoology and microbiology or as classical and modern.
II.
'Modern biology' is a euphemism for the structural aspects of biology.
III. Ecology is a biological thread
that gives us a holistic perspective to biology.
IV. The essence of biological understanding is to know how
organisms interact with other organisms and physical habitats as a group. Choose the correct option:
correct?
I. Biology is presented either as botany, zoology and microbiology or as classical and modern.
II.
'Modern biology' is a euphemism for the structural aspects of biology.
III. Ecology is a biological thread
that gives us a holistic perspective to biology.
IV. The essence of biological understanding is to know how
organisms interact with other organisms and physical habitats as a group. Choose the correct option:
6.Given below are two statements, one is labelled as Assertion (A) and the other is labelled as Reason
(R): Assertion (A): Organisms, while remaining individuals, interact with other organisms and physical
habitats to behave like organised wholes.
Reason (R): Organised wholes manifest in biological systems
strictly at the level of populations and communities, never at the level of the ecosystem. In the light of the
above statements, choose the correct answer:
(R): Assertion (A): Organisms, while remaining individuals, interact with other organisms and physical
habitats to behave like organised wholes.
Reason (R): Organised wholes manifest in biological systems
strictly at the level of populations and communities, never at the level of the ecosystem. In the light of the
above statements, choose the correct answer:
7.According to the introductory paragraph of Chapter 11, the complexity of our fascinatingly diverse
living world can be investigated at various levels of biological organisation. Which of the following is the
correct, complete list of these levels explicitly listed in the text?
I. Macromolecules, cells, tissues, organs.
II.
Individual organisms, populations.
III. Communities, ecosystems, biomes.
IV. Organ systems, families,
species. Choose the correct option:
living world can be investigated at various levels of biological organisation. Which of the following is the
correct, complete list of these levels explicitly listed in the text?
I. Macromolecules, cells, tissues, organs.
II.
Individual organisms, populations.
III. Communities, ecosystems, biomes.
IV. Organ systems, families,
species. Choose the correct option:
8.Given below are two statements, one is labelled as Assertion (A) and the other is labelled as Reason
(R): Assertion (A): When we observe the bulbul singing in the morning, the question 'How does the bird
sing?' seeks the significance of the singing process.
Reason (R): The 'why-type' questions seek the
evolutionary rationale or significance behind a biological process. In the light of the above statements,
choose the correct answer:
(R): Assertion (A): When we observe the bulbul singing in the morning, the question 'How does the bird
sing?' seeks the significance of the singing process.
Reason (R): The 'why-type' questions seek the
evolutionary rationale or significance behind a biological process. In the light of the above statements,
choose the correct answer:
9.Consider the following statements regarding the biological explanations for the bulbul's song: I. The
operational mechanism of the song involves the operation of the voice box in the bird.
II. The mechanism
also involves the vibrating bone in the bird's voice apparatus.
III. The ecological significance of the song is
related to the bird's need to mark its physical territory against intruders.
IV. The ultimate significance of
the song lies in the bird's need to communicate with its mate during the breeding season. Which of the
statements given above are correct according to the NCERT text?
operational mechanism of the song involves the operation of the voice box in the bird.
II. The mechanism
also involves the vibrating bone in the bird's voice apparatus.
III. The ecological significance of the song is
related to the bird's need to mark its physical territory against intruders.
IV. The ultimate significance of
the song lies in the bird's need to communicate with its mate during the breeding season. Which of the
statements given above are correct according to the NCERT text?
10.Given below are two statements, one is labelled as Assertion (A) and the other is labelled as Reason
(R): Assertion (A): Night-blooming flowers are generally white, and cacti have numerous thorns.
Reason
(R): White coloration in night flowers minimizes the metabolic cost of pigment synthesis, while thorns
represent specialized leaves modified for water storage. In the light of the above statements, choose the
correct answer:
(R): Assertion (A): Night-blooming flowers are generally white, and cacti have numerous thorns.
Reason
(R): White coloration in night flowers minimizes the metabolic cost of pigment synthesis, while thorns
represent specialized leaves modified for water storage. In the light of the above statements, choose the
correct answer:
11.According to the introductory section of Chapter 11, which of the following represent the exact
questions that one comes up with when observing nature with a scientific frame of mind?
I. Why are
night-blooming flowers generally white?
II. How does the bee know which flower has nectar?
III. Why
does cactus have so many thorns?
IV. How does the chick recognize her own mother? Choose the correct
option:
questions that one comes up with when observing nature with a scientific frame of mind?
I. Why are
night-blooming flowers generally white?
II. How does the bee know which flower has nectar?
III. Why
does cactus have so many thorns?
IV. How does the chick recognize her own mother? Choose the correct
option:
12.Given below are two statements, one is labelled as Assertion (A) and the other is labelled as Reason
(R): Assertion (A): Ecology is basically concerned with four levels of biological organisation.
Reason (R):
These four levels of organization are: organisms, populations, communities, and biomes. In the light of the
above statements, choose the correct answer:
(R): Assertion (A): Ecology is basically concerned with four levels of biological organisation.
Reason (R):
These four levels of organization are: organisms, populations, communities, and biomes. In the light of the
above statements, choose the correct answer:
13.Consider the following statements regarding the ecological definition of a population: I. In nature,
we rarely find isolated, single individuals of any species.
II. A majority of individuals live in groups in a
well-defined geographical area.
III. A population consists of individuals that share or compete for similar
resources and potentially interbreed.
IV. The term interbreeding implies that asexual reproduction is
strictly excluded from forming a population in ecological studies. Which of the statements given above are
correct according to the NCERT textbook?
we rarely find isolated, single individuals of any species.
II. A majority of individuals live in groups in a
well-defined geographical area.
III. A population consists of individuals that share or compete for similar
resources and potentially interbreed.
IV. The term interbreeding implies that asexual reproduction is
strictly excluded from forming a population in ecological studies. Which of the statements given above are
correct according to the NCERT textbook?
14.Given below are two statements, one is labelled as Assertion (A) and the other is labelled as Reason
(R): Assertion (A): Teakwood trees in a forest tract and lotus plants in a pond represent valid examples of
populations.
Reason (R): Bacteria in a culture plate, cormorants in a wetland, and rats in an abandoned
dwelling are also explicitly listed in NCERT as examples of populations. In the light of the above
statements, choose the correct answer:
(R): Assertion (A): Teakwood trees in a forest tract and lotus plants in a pond represent valid examples of
populations.
Reason (R): Bacteria in a culture plate, cormorants in a wetland, and rats in an abandoned
dwelling are also explicitly listed in NCERT as examples of populations. In the light of the above
statements, choose the correct answer:
15.Consider the following statements regarding the evolutionary dynamics of individuals versus
populations: I. The individual organism is the one that has to cope with a changed environment.
II.
Natural selection operates at the individual level to evolve the desired traits.
III. It is at the population
level that natural selection operates to evolve the desired traits.
IV. Population ecology is an important
area because it links ecology to population genetics and evolution. Which of the statements given above
are correct according to the NCERT textbook?
populations: I. The individual organism is the one that has to cope with a changed environment.
II.
Natural selection operates at the individual level to evolve the desired traits.
III. It is at the population
level that natural selection operates to evolve the desired traits.
IV. Population ecology is an important
area because it links ecology to population genetics and evolution. Which of the statements given above
are correct according to the NCERT textbook?
16.Given below are two statements, one is labelled as Assertion (A) and the other is labelled as Reason
(R): Assertion (A): A population has certain attributes whereas, an individual organism does not.
Reason
(R): An individual may have births and deaths, but a population has birth rates and death rates. In the
light of the above statements, choose the correct answer:
(R): Assertion (A): A population has certain attributes whereas, an individual organism does not.
Reason
(R): An individual may have births and deaths, but a population has birth rates and death rates. In the
light of the above statements, choose the correct answer:
17.Consider the following statements regarding the birth rate calculation of a pond population of lotus
plants: I. The initial population of lotus plants in the pond last year was 20.
II. Through reproduction, 8
new plants were added during the year.
III. The current population of lotus plants is 28.
IV. The birth rate
is calculated as 0.28 offspring per lotus per year. Which of the statements given above are correct
according to the NCERT text?
plants: I. The initial population of lotus plants in the pond last year was 20.
II. Through reproduction, 8
new plants were added during the year.
III. The current population of lotus plants is 28.
IV. The birth rate
is calculated as 0.28 offspring per lotus per year. Which of the statements given above are correct
according to the NCERT text?
18.Given below are two statements, one is labelled as Assertion (A) and the other is labelled as Reason
(R): Assertion (A): In a laboratory population of 40 fruitflies, if 4 individuals died during a week, the
death rate is 0.1 individuals per fruitfly per week.
Reason (R): The death rate in a population is calculated
by dividing the number of deaths during a specified interval by the initial population size during that
period.
In the light of the above statements, choose the correct answer:
(R): Assertion (A): In a laboratory population of 40 fruitflies, if 4 individuals died during a week, the
death rate is 0.1 individuals per fruitfly per week.
Reason (R): The death rate in a population is calculated
by dividing the number of deaths during a specified interval by the initial population size during that
period.
In the light of the above statements, choose the correct answer:
19.Consider the following statements regarding 'sex ratio' as a population attribute: I. An individual
organism has a sex ratio, whereas a population is either male or female.
II. An individual is either a male
or a female, but a population has a sex ratio.
III. If 60 per cent of a population are females and 40 per cent
are males, the sex ratio is expressed as a population statistic.
IV. Sex ratio is defined only for organisms
reproducing via obligate parthenogenesis. Which of the statements given above are correct according to
the NCERT textbook?
organism has a sex ratio, whereas a population is either male or female.
II. An individual is either a male
or a female, but a population has a sex ratio.
III. If 60 per cent of a population are females and 40 per cent
are males, the sex ratio is expressed as a population statistic.
IV. Sex ratio is defined only for organisms
reproducing via obligate parthenogenesis. Which of the statements given above are correct according to
the NCERT textbook?
20.Given below are two statements, one is labelled as Assertion (A) and the other is labelled as Reason
(R): Assertion (A): For the human population, age pyramids generally show the age distribution of males
and females in a single diagram.
Reason (R): An age pyramid represents the plot of the percentage of
individuals of a given age or age group for the population. In the light of the above statements, choose the
correct answer:
(R): Assertion (A): For the human population, age pyramids generally show the age distribution of males
and females in a single diagram.
Reason (R): An age pyramid represents the plot of the percentage of
individuals of a given age or age group for the population. In the light of the above statements, choose the
correct answer:
21.According to the NCERT textbook, the shape of the age pyramids reflects the growth status of a
population. Which of the following represent the correct growth status options?
I. Growing (expanding)
II. Stable III. Declining IV. Fluctuating Choose the correct option:
population. Which of the following represent the correct growth status options?
I. Growing (expanding)
II. Stable III. Declining IV. Fluctuating Choose the correct option:
22.Given below are two statements, one is labelled as Assertion (A) and the other is labelled as Reason
(R): Assertion (A): We always evaluate ecological processes in a population in terms of any change in the
population size.
Reason (R): The size of the population in nature is a static parameter that represents the
evolutionary climax of a species.
In the light of the above statements, choose the correct answer:
(R): Assertion (A): We always evaluate ecological processes in a population in terms of any change in the
population size.
Reason (R): The size of the population in nature is a static parameter that represents the
evolutionary climax of a species.
In the light of the above statements, choose the correct answer:
23.Consider the following statements regarding the extreme ranges of population size (N) in nature: I.
Population size can be as low as <10 in a given habitat.
II. An example of a low population size is the
Siberian cranes at Bharatpur wetlands in any year.
III. Population size can go into millions, such as
Chlamydomonas in a pond.
IV. The Siberian cranes are described as migrating from the wetlands of
Bharatpur to the saltwater lagoons of Chilika. Which of the statements given above are correct according
to the NCERT textbook?
Population size can be as low as <10 in a given habitat.
II. An example of a low population size is the
Siberian cranes at Bharatpur wetlands in any year.
III. Population size can go into millions, such as
Chlamydomonas in a pond.
IV. The Siberian cranes are described as migrating from the wetlands of
Bharatpur to the saltwater lagoons of Chilika. Which of the statements given above are correct according
to the NCERT textbook?
24.Given below are two statements, one is labelled as Assertion (A) and the other is labelled as Reason
(R): Assertion (A): Stating that the population density of a single huge banyan tree is low relative to 200
carrot grass plants underestimates its ecological role.
Reason (R): In cases where a single large canopy
tree is compared to numerous small weeds, per cent cover or biomass is a more meaningful measure of
population size than total number.
In the light of the above statements, choose the correct answer:
(R): Assertion (A): Stating that the population density of a single huge banyan tree is low relative to 200
carrot grass plants underestimates its ecological role.
Reason (R): In cases where a single large canopy
tree is compared to numerous small weeds, per cent cover or biomass is a more meaningful measure of
population size than total number.
In the light of the above statements, choose the correct answer:
25.Consider the following statements regarding the invasive weed carrot grass mentioned in Section
11.1.1: I. The scientific name of carrot grass is Parthenium hysterophorus.
II. It is used in the text as a
contrast against a single huge banyan tree with a large canopy.
III. The density of Parthenium in the
example is exactly 200 plants.
IV. Parthenium is described in the text as an endemic species that has lived
in India for centuries. Which of the statements given above are correct according to the NCERT textbook?
11.1.1: I. The scientific name of carrot grass is Parthenium hysterophorus.
II. It is used in the text as a
contrast against a single huge banyan tree with a large canopy.
III. The density of Parthenium in the
example is exactly 200 plants.
IV. Parthenium is described in the text as an endemic species that has lived
in India for centuries. Which of the statements given above are correct according to the NCERT textbook?
26.Given below are two statements, one is labelled as Assertion (A) and the other is labelled as Reason
(R): Assertion (A): Total number is not an easily adoptable measure if the population is huge and counting
is impossible or time-consuming.
Reason (R): For a dense laboratory culture of bacteria in a petri dish,
NCERT suggests that counting each individual cell is the only scientifically valid report. In the light of the
above statements, choose the correct answer:
(R): Assertion (A): Total number is not an easily adoptable measure if the population is huge and counting
is impossible or time-consuming.
Reason (R): For a dense laboratory culture of bacteria in a petri dish,
NCERT suggests that counting each individual cell is the only scientifically valid report. In the light of the
above statements, choose the correct answer:
27.Consider the following statements regarding 'relative density' as an ecological measure: I.
Sometimes, there is no need to know the absolute population densities.
II. Relative densities serve the
purpose equally well for certain ecological investigations.
III. The number of fish caught per trap is a good
enough measure of its total population density in a lake.
IV. The fish per trap is a direct measure of the
absolute population size of the lake. Which of the statements given above are correct according to the
NCERT textbook?
Sometimes, there is no need to know the absolute population densities.
II. Relative densities serve the
purpose equally well for certain ecological investigations.
III. The number of fish caught per trap is a good
enough measure of its total population density in a lake.
IV. The fish per trap is a direct measure of the
absolute population size of the lake. Which of the statements given above are correct according to the
NCERT textbook?
28.Given below are two statements, one is labelled as Assertion (A) and the other is labelled as Reason
(R): Assertion (A): We are mostly obliged to estimate population sizes indirectly, without actually counting
them or seeing them.
Reason (R): The tiger census in our national parks and tiger reserves is often based
on pug marks and fecal pellets.
In the light of the above statements, choose the correct answer:
(R): Assertion (A): We are mostly obliged to estimate population sizes indirectly, without actually counting
them or seeing them.
Reason (R): The tiger census in our national parks and tiger reserves is often based
on pug marks and fecal pellets.
In the light of the above statements, choose the correct answer:
29.Consider the following statements regarding the factors that influence population growth: I. The size
of a population for any species is not a static parameter.
II. Population density keeps changing with time
depending on various factors.
III. The factors include food availability, predation pressure, and adverse
weather.
IV. Adverse weather is described as the only factor that causes permanent fluctuations. Which of
the statements given above are correct according to the NCERT textbook?
of a population for any species is not a static parameter.
II. Population density keeps changing with time
depending on various factors.
III. The factors include food availability, predation pressure, and adverse
weather.
IV. Adverse weather is described as the only factor that causes permanent fluctuations. Which of
the statements given above are correct according to the NCERT textbook?
30.Given below are two statements, one is labelled as Assertion (A) and the other is labelled as Reason
(R): Assertion (A): Changes in population density give us some idea of whether a population is flourishing
or declining.
Reason (R): The density of a population in a given habitat during a given period is
determined primarily by changes in six basic physiological processes. In the light of the above statements,
choose the correct answer:
(R): Assertion (A): Changes in population density give us some idea of whether a population is flourishing
or declining.
Reason (R): The density of a population in a given habitat during a given period is
determined primarily by changes in six basic physiological processes. In the light of the above statements,
choose the correct answer:
31.Consider the following statements regarding the age structure and cohorts used in constructing age
pyramids: I. A population at any given time is composed of individuals of different ages.
II. The age
groups are divided into pre-reproductive, reproductive, and post-reproductive cohorts.
III. The shape of
the pyramids reflects the metabolic status of the individual organisms.
IV. The age distribution is plotted
as the per cent individuals of a given age or age group for the population. Which of the statements given
above are correct according to the NCERT textbook?
pyramids: I. A population at any given time is composed of individuals of different ages.
II. The age
groups are divided into pre-reproductive, reproductive, and post-reproductive cohorts.
III. The shape of
the pyramids reflects the metabolic status of the individual organisms.
IV. The age distribution is plotted
as the per cent individuals of a given age or age group for the population. Which of the statements given
above are correct according to the NCERT textbook?
32.Given below are two statements, one is labelled as Assertion (A) and the other is labelled as Reason
(R): Assertion (A): In a growing or expanding population pyramid, the pre-reproductive cohort forms the
largest segment of the population.
Reason (R): The pre-reproductive cohort is rapidly shrinking over time,
which will eventually narrow the reproductive base in the next generation. In the light of the above
statements, choose the correct answer:
(R): Assertion (A): In a growing or expanding population pyramid, the pre-reproductive cohort forms the
largest segment of the population.
Reason (R): The pre-reproductive cohort is rapidly shrinking over time,
which will eventually narrow the reproductive base in the next generation. In the light of the above
statements, choose the correct answer:
33.Consider the following statements regarding the cohort sizes in stable and declining age pyramids: I.
In a stable population, the pre-reproductive and reproductive individuals are nearly equal in number.
II.
In a declining population, the pre-reproductive cohort is smaller than the reproductive cohort.
III. The
stable pyramid is bell-shaped, while the declining pyramid is urn-shaped.
IV. In all types of pyramids, the
post-reproductive cohort always forms the broadest segment of the diagram. Which of the statements
given above are correct according to the NCERT textbook representations?
In a stable population, the pre-reproductive and reproductive individuals are nearly equal in number.
II.
In a declining population, the pre-reproductive cohort is smaller than the reproductive cohort.
III. The
stable pyramid is bell-shaped, while the declining pyramid is urn-shaped.
IV. In all types of pyramids, the
post-reproductive cohort always forms the broadest segment of the diagram. Which of the statements
given above are correct according to the NCERT textbook representations?
34.Given below are two statements, one is labelled as Assertion (A) and the other is labelled as Reason
(R): Assertion (A): Population size in ecology is technically designated as population density and
represented by the letter N.
Reason (R): Population density must necessarily be measured in numbers of
individuals only, to maintain global scientific uniformity. In the light of the above statements, choose the
correct answer:
(R): Assertion (A): Population size in ecology is technically designated as population density and
represented by the letter N.
Reason (R): Population density must necessarily be measured in numbers of
individuals only, to maintain global scientific uniformity. In the light of the above statements, choose the
correct answer:
35.Consider the following quantitative parameters described in the population attributes section of
Chapter 11: I. In the pond example, 8 new plants were added to an initial population of 20 lotus plants.
II.
The resulting birth rate is calculated as 0.4 offspring per lotus per year.
III. In the laboratory fruitfly
population, 4 individuals died out of a starting population of 40 fruitflies.
IV. The resulting death rate in
the fruitfly population is calculated as 0.1 individuals per fruitfly per year. Which of the statements given
above are correct according to the NCERT textbook?
Chapter 11: I. In the pond example, 8 new plants were added to an initial population of 20 lotus plants.
II.
The resulting birth rate is calculated as 0.4 offspring per lotus per year.
III. In the laboratory fruitfly
population, 4 individuals died out of a starting population of 40 fruitflies.
IV. The resulting death rate in
the fruitfly population is calculated as 0.1 individuals per fruitfly per year. Which of the statements given
above are correct according to the NCERT textbook?
36.Given below are two statements, one is labelled as Assertion (A) and the other is labelled as Reason
(R): Assertion (A): For certain ecological investigations, there is no need to know the absolute population
densities.
Reason (R): Relative densities, such as the number of fish caught per trap, serve the purpose
equally well for lake population assessments. In the light of the above statements, choose the correct
answer:
(R): Assertion (A): For certain ecological investigations, there is no need to know the absolute population
densities.
Reason (R): Relative densities, such as the number of fish caught per trap, serve the purpose
equally well for lake population assessments. In the light of the above statements, choose the correct
answer:
37.Consider the following statements regarding the estimation of tiger populations in national parks
and reserves: I. We are mostly obliged to estimate population sizes indirectly, without actually counting or
seeing the animals.
II. The tiger census in national parks is often based on pug marks.
III. The census is
also based on fecal pellets.
IV. The census is strictly conducted by using camera-trap DNA sequencing
only. Which of the statements given above are correct according to the NCERT textbook?
and reserves: I. We are mostly obliged to estimate population sizes indirectly, without actually counting or
seeing the animals.
II. The tiger census in national parks is often based on pug marks.
III. The census is
also based on fecal pellets.
IV. The census is strictly conducted by using camera-trap DNA sequencing
only. Which of the statements given above are correct according to the NCERT textbook?
38.Given below are two statements, one is labelled as Assertion (A) and the other is labelled as Reason
(R): Assertion (A): The size of a population for any species in nature keeps changing with time depending
on food, predators, and weather.
Reason (R): Changes in population density provide some idea of whether
a population is flourishing or declining in a given habitat. In the light of the above statements, choose the
correct answer:
(R): Assertion (A): The size of a population for any species in nature keeps changing with time depending
on food, predators, and weather.
Reason (R): Changes in population density provide some idea of whether
a population is flourishing or declining in a given habitat. In the light of the above statements, choose the
correct answer:
39.Consider the following statements regarding the four basic processes that fluctuate population
density: I. Natality refers to the number of births during a given period in the population that are added
to the initial density.
II. Mortality is the number of deaths in the population during a given period.
III.
Immigration is the number of individuals of the same species that have come into the habitat from
elsewhere during the time period under consideration.
IV. Emigration is the number of individuals of the
population who left the habitat and gone elsewhere during the time period under consideration. Which of
the statements given above are correct according to the NCERT textbook?
density: I. Natality refers to the number of births during a given period in the population that are added
to the initial density.
II. Mortality is the number of deaths in the population during a given period.
III.
Immigration is the number of individuals of the same species that have come into the habitat from
elsewhere during the time period under consideration.
IV. Emigration is the number of individuals of the
population who left the habitat and gone elsewhere during the time period under consideration. Which of
the statements given above are correct according to the NCERT textbook?
40.Given below are two statements, one is labelled as Assertion (A) and the other is labelled as Reason
(R): Assertion (A): Natality and emigration contribute to an increase in population density.
Reason (R):
Mortality and immigration contribute to a decrease in population density. In the light of the above
statements, choose the correct answer:
(R): Assertion (A): Natality and emigration contribute to an increase in population density.
Reason (R):
Mortality and immigration contribute to a decrease in population density. In the light of the above
statements, choose the correct answer:
41.If N is the population density at time t, which of the following represent the correct mathematical
representation of the density at time t + 1 according to Section 11.1.2?
I. Nt+1 = Nt + [(B + I) – (D + E)] II.
Nt+1 = Nt + B + I – D – E III. Nt+1 = Nt + [(B - D) + (I - E)] IV. Nt+1 = Nt + [(B + E) – (D + I)] Choose the
correct option:
representation of the density at time t + 1 according to Section 11.1.2?
I. Nt+1 = Nt + [(B + I) – (D + E)] II.
Nt+1 = Nt + B + I – D – E III. Nt+1 = Nt + [(B - D) + (I - E)] IV. Nt+1 = Nt + [(B + E) – (D + I)] Choose the
correct option:
42.Given below are two statements, one is labelled as Assertion (A) and the other is labelled as Reason
(R): Assertion (A): Population density will increase if the number of births plus the number of immigrants
(B + I) is more than the number of deaths plus the number of emigrants (D + E).
Reason (R): Under
normal conditions, births and deaths are the most important factors influencing population density. In the
light of the above statements, choose the correct answer:
(R): Assertion (A): Population density will increase if the number of births plus the number of immigrants
(B + I) is more than the number of deaths plus the number of emigrants (D + E).
Reason (R): Under
normal conditions, births and deaths are the most important factors influencing population density. In the
light of the above statements, choose the correct answer:
43.Consider the following statements regarding the factors that influence population growth under
special environmental conditions: I. Under normal conditions, births and deaths are the most important
factors influencing population density.
II. Immigration and emigration assume importance only under
special conditions.
III. If a new habitat is just being colonised, birth rates contribute more significantly to
population growth than immigration.
IV. In a newly colonised habitat, immigration may contribute more
significantly to population growth than birth rates. Which of the statements given above are correct
according to the NCERT textbook?
special environmental conditions: I. Under normal conditions, births and deaths are the most important
factors influencing population density.
II. Immigration and emigration assume importance only under
special conditions.
III. If a new habitat is just being colonised, birth rates contribute more significantly to
population growth than immigration.
IV. In a newly colonised habitat, immigration may contribute more
significantly to population growth than birth rates. Which of the statements given above are correct
according to the NCERT textbook?
44.Given below are two statements, one is labelled as Assertion (A) and the other is labelled as Reason
(R): Assertion (A): We have been concerned about unbridled human population growth and the problems
created by it in our country.
Reason (R): Resource (food and space) availability is obviously essential for
the unimpeded growth of a population.
In the light of the above statements, choose the correct answer:
(R): Assertion (A): We have been concerned about unbridled human population growth and the problems
created by it in our country.
Reason (R): Resource (food and space) availability is obviously essential for
the unimpeded growth of a population.
In the light of the above statements, choose the correct answer:
45.Consider the following statements regarding the conditions required for exponential population
growth: I. Ideally, when resources in the habitat are unlimited, each species has the ability to realise fully
its innate potential to grow in number.
II. This innate growth potential was famously observed by Darwin
while developing his theory of natural selection.
III. Under unlimited resource conditions, the population
grows in an exponential or geometric fashion.
IV. Under unlimited resource conditions, the population
grows in a logistic or arithmetic fashion. Which of the statements given above are correct according to the
NCERT textbook?
growth: I. Ideally, when resources in the habitat are unlimited, each species has the ability to realise fully
its innate potential to grow in number.
II. This innate growth potential was famously observed by Darwin
while developing his theory of natural selection.
III. Under unlimited resource conditions, the population
grows in an exponential or geometric fashion.
IV. Under unlimited resource conditions, the population
grows in a logistic or arithmetic fashion. Which of the statements given above are correct according to the
NCERT textbook?
46.Given below are two statements, one is labelled as Assertion (A) and the other is labelled as Reason
(R): Assertion (A): In a population of size N, the birth rates (per capita births) are b and death rates (per
capita deaths) are d.
Reason (R): The increase or decrease in population size N during a unit time period t
is mathematically represented as dN/dt = (b – d) x N. In the light of the above statements, choose the
correct answer:
(R): Assertion (A): In a population of size N, the birth rates (per capita births) are b and death rates (per
capita deaths) are d.
Reason (R): The increase or decrease in population size N during a unit time period t
is mathematically represented as dN/dt = (b – d) x N. In the light of the above statements, choose the
correct answer:
47.Consider the following statements regarding the parameter r in the growth equation dN/dt = rN: I.
The parameter r is defined as b - d (where b is birth rate and d is death rate).
II. The parameter r is called
the 'intrinsic rate of natural increase'.
III. The parameter r is a very important parameter chosen for
assessing impacts of any biotic or abiotic factor on population growth.
IV. The parameter r represents the
total number of individuals added to the population per unit time. Which of the statements given above
are correct according to the NCERT textbook?
The parameter r is defined as b - d (where b is birth rate and d is death rate).
II. The parameter r is called
the 'intrinsic rate of natural increase'.
III. The parameter r is a very important parameter chosen for
assessing impacts of any biotic or abiotic factor on population growth.
IV. The parameter r represents the
total number of individuals added to the population per unit time. Which of the statements given above
are correct according to the NCERT textbook?
48.Given below are two statements, one is labelled as Assertion (A) and the other is labelled as Reason
(R): Assertion (A): For the Norway rat, the intrinsic rate of natural increase (r) is exactly 0.12.
Reason
(R): For the flour beetle, the intrinsic rate of natural increase (r) is exactly 0.015. In the light of the above
statements, choose the correct answer:
(R): Assertion (A): For the Norway rat, the intrinsic rate of natural increase (r) is exactly 0.12.
Reason
(R): For the flour beetle, the intrinsic rate of natural increase (r) is exactly 0.015. In the light of the above
statements, choose the correct answer:
49.Consider the following statements regarding the historical human population r value in India: I. In
1981, the r value for the human population in India was exactly 0.0205.
II. In 1981, the r value for the
human population in India was exactly 2.05 per cent.
III. The year in which the human population r value
was recorded as 0.0205 was 1991.
IV. To calculate the current r value, one needs to know both the birth
rates and the death rates of the population. Which of the statements given above are correct according to
the NCERT textbook?
1981, the r value for the human population in India was exactly 0.0205.
II. In 1981, the r value for the
human population in India was exactly 2.05 per cent.
III. The year in which the human population r value
was recorded as 0.0205 was 1991.
IV. To calculate the current r value, one needs to know both the birth
rates and the death rates of the population. Which of the statements given above are correct according to
the NCERT textbook?
50.Given below are two statements, one is labelled as Assertion (A) and the other is labelled as Reason
(R): Assertion (A): The exponential or geometric growth pattern of a population results in a J-shaped
curve when we plot population density in relation to time.
Reason (R): A J-shaped curve represents the
dynamic transition where resources become limiting, causing the population to hit an asymptote. In the
light of the above statements, choose the correct answer:
(R): Assertion (A): The exponential or geometric growth pattern of a population results in a J-shaped
curve when we plot population density in relation to time.
Reason (R): A J-shaped curve represents the
dynamic transition where resources become limiting, causing the population to hit an asymptote. In the
light of the above statements, choose the correct answer:
51.Consider the following statements regarding the integral form of the exponential growth equation: I.
The integral form is written as Nt = N0 e^rt.
II. Nt represents the population density after time t.
III. N0
represents the population density at time zero.
IV. The variable e represents the base of natural
logarithms, and its value is exactly 2.71828. Which of the statements given above are correct according to
the NCERT textbook?
The integral form is written as Nt = N0 e^rt.
II. Nt represents the population density after time t.
III. N0
represents the population density at time zero.
IV. The variable e represents the base of natural
logarithms, and its value is exactly 2.71828. Which of the statements given above are correct according to
the NCERT textbook?
52.Given below are two statements, one is labelled as Assertion (A) and the other is labelled as Reason
(R): Assertion (A): Any species growing exponentially under unlimited resource conditions can reach
enormous population densities in a short time.
Reason (R): Darwin showed how even a slow-growing
animal like the elephant could reach enormous numbers in the absence of checks. In the light of the above
statements, choose the correct answer:
(R): Assertion (A): Any species growing exponentially under unlimited resource conditions can reach
enormous population densities in a short time.
Reason (R): Darwin showed how even a slow-growing
animal like the elephant could reach enormous numbers in the absence of checks. In the light of the above
statements, choose the correct answer:
53.Consider the following statements regarding the anecdote of the king and the minister sat for a chess
game: I. The minister won the chess game and demanded a bet calculated by placing wheat grains on the
chess board.
II. The procedure was placing 1 grain in Square 1, 2 in Square 2, 4 in Square 3, 8 in Square 4,
doubling each time.
III. The king realized to his dismay that by the time he covered half the chess board,
all the wheat in his entire kingdom was inadequate.
IV. The total number of squares on the chess board to
be filled was 64. Which of the statements given above are correct according to the NCERT textbook?
game: I. The minister won the chess game and demanded a bet calculated by placing wheat grains on the
chess board.
II. The procedure was placing 1 grain in Square 1, 2 in Square 2, 4 in Square 3, 8 in Square 4,
doubling each time.
III. The king realized to his dismay that by the time he covered half the chess board,
all the wheat in his entire kingdom was inadequate.
IV. The total number of squares on the chess board to
be filled was 64. Which of the statements given above are correct according to the NCERT textbook?
54.Given below are two statements, one is labelled as Assertion (A) and the other is labelled as Reason
(R): Assertion (A): A single Paramecium doubling in numbers every day through binary fission would
reach a mind-boggling population size in 64 days under unlimited resources.
Reason (R): Paramecium is a
multicellular eukaryotic organism that utilizes complex syngamy to double its population density in a
geometric progression.
In the light of the above statements, choose the correct answer:
(R): Assertion (A): A single Paramecium doubling in numbers every day through binary fission would
reach a mind-boggling population size in 64 days under unlimited resources.
Reason (R): Paramecium is a
multicellular eukaryotic organism that utilizes complex syngamy to double its population density in a
geometric progression.
In the light of the above statements, choose the correct answer:
55.Consider the following statements regarding the ecological realities of resource availability in nature:
I. No population of any species in nature has at its disposal unlimited resources to permit permanent
exponential growth.
II. The limitation of resources leads to competition between individuals for limited
resources.
III. Eventually, the 'fittest' individual will survive and reproduce in the habitat.
IV. The
governments of many countries have introduced various restraints to maximize human population growth
rates. Which of the statements given above are correct according to the NCERT textbook?
I. No population of any species in nature has at its disposal unlimited resources to permit permanent
exponential growth.
II. The limitation of resources leads to competition between individuals for limited
resources.
III. Eventually, the 'fittest' individual will survive and reproduce in the habitat.
IV. The
governments of many countries have introduced various restraints to maximize human population growth
rates. Which of the statements given above are correct according to the NCERT textbook?
56.Given below are two statements, one is labelled as Assertion (A) and the other is labelled as Reason
(R): Assertion (A): A given habitat has enough resources to support a maximum possible number of a
species, beyond which no further growth is possible.
Reason (R): This maximum limit of support is called
nature's carrying capacity (K) for that species in that habitat. In the light of the above statements, choose
the correct answer:
(R): Assertion (A): A given habitat has enough resources to support a maximum possible number of a
species, beyond which no further growth is possible.
Reason (R): This maximum limit of support is called
nature's carrying capacity (K) for that species in that habitat. In the light of the above statements, choose
the correct answer:
57.According to the NCERT textbook, which of the following represents the correct, sequentially
ordered list of phases shown by a population growing in a habitat with limited resources?
I. Lag phase.
II.
Phase of acceleration.
III. Phase of deceleration.
IV. Asymptote. Choose the correct sequence from the
options below:
ordered list of phases shown by a population growing in a habitat with limited resources?
I. Lag phase.
II.
Phase of acceleration.
III. Phase of deceleration.
IV. Asymptote. Choose the correct sequence from the
options below:
58.Given below are two statements, one is labelled as Assertion (A) and the other is labelled as Reason
(R): Assertion (A): The type of population growth resulting in a sigmoid curve under limited resources is
called Verhulst-Pearl Logistic Growth.
Reason (R): The equation that describes this logistic growth is:
dN/dt = rN * [(K - N) / K].
In the light of the above statements, choose the correct answer:
(R): Assertion (A): The type of population growth resulting in a sigmoid curve under limited resources is
called Verhulst-Pearl Logistic Growth.
Reason (R): The equation that describes this logistic growth is:
dN/dt = rN * [(K - N) / K].
In the light of the above statements, choose the correct answer:
59.Consider the following statements regarding the variables used in the Verhulst-Pearl Logistic
Growth equation: dN/dt = rN * [(K - N) / K]: I. N represents the population density at time t.
II. r
represents the intrinsic rate of natural increase.
III. K represents the carrying capacity.
IV. The term (K -
N) / K represents the environmental resistance or the fraction of resources still available. Which of the
statements given above are correct according to the NCERT textbook?
Growth equation: dN/dt = rN * [(K - N) / K]: I. N represents the population density at time t.
II. r
represents the intrinsic rate of natural increase.
III. K represents the carrying capacity.
IV. The term (K -
N) / K represents the environmental resistance or the fraction of resources still available. Which of the
statements given above are correct according to the NCERT textbook?
60.Given below are two statements, one is labelled as Assertion (A) and the other is labelled as Reason
(R): Assertion (A): The logistic growth model is considered a more realistic model for most animal
populations in nature.
Reason (R): Resources for growth for most animal populations are finite and
become limiting sooner or later.
In the light of the above statements, choose the correct answer:
(R): Assertion (A): The logistic growth model is considered a more realistic model for most animal
populations in nature.
Reason (R): Resources for growth for most animal populations are finite and
become limiting sooner or later.
In the light of the above statements, choose the correct answer:
61.Consider the following statements regarding the suggestions made in Section 11.1.2 for analyzing
population data in India: I. The text suggests gathering population figures for India for the last 100 years
from Government Census data.
II. The text suggests plotting these census figures to check which growth
pattern is evident.
III. The census data is explicitly described as representing a perfect Verhulst-Pearl
logistic asymptote since 1947.
IV. The text suggests that the Indian human population growth pattern
shows a J-shaped curve that has transitioned into a stable asymptote. Which of the statements given above
are correct according to the NCERT textbook?
population data in India: I. The text suggests gathering population figures for India for the last 100 years
from Government Census data.
II. The text suggests plotting these census figures to check which growth
pattern is evident.
III. The census data is explicitly described as representing a perfect Verhulst-Pearl
logistic asymptote since 1947.
IV. The text suggests that the Indian human population growth pattern
shows a J-shaped curve that has transitioned into a stable asymptote. Which of the statements given above
are correct according to the NCERT textbook?
62.Given below are two statements, one is labelled as Assertion (A) and the other is labelled as Reason
(R): Assertion (A): Populations evolve to maximize their reproductive fitness, also called Darwinian
fitness, in the habitat in which they live.
Reason (R): Darwinian fitness is technically represented by a high
r value (intrinsic rate of natural increase) in the population growth models. In the light of the above
statements, choose the correct answer:
(R): Assertion (A): Populations evolve to maximize their reproductive fitness, also called Darwinian
fitness, in the habitat in which they live.
Reason (R): Darwinian fitness is technically represented by a high
r value (intrinsic rate of natural increase) in the population growth models. In the light of the above
statements, choose the correct answer:
63.Consider the following statements regarding the lifetime breeding frequencies of different
organisms: I. Some organisms breed only once in their lifetime.
II. Examples of once-in-a-lifetime
breeders are the Pacific salmon fish and bamboo.
III. Some organisms breed many times during their
lifetime.
IV. Examples of multiple-lifetime breeders are most birds and mammals. Which of the statements
given above are correct according to the NCERT textbook?
organisms: I. Some organisms breed only once in their lifetime.
II. Examples of once-in-a-lifetime
breeders are the Pacific salmon fish and bamboo.
III. Some organisms breed many times during their
lifetime.
IV. Examples of multiple-lifetime breeders are most birds and mammals. Which of the statements
given above are correct according to the NCERT textbook?
64.Given below are two statements, one is labelled as Assertion (A) and the other is labelled as Reason
(R): Assertion (A): Bamboo and Pacific salmon fish breed many times during their lifetime to maximize
larval recruitment.
Reason (R): Most birds and mammals breed only once in their lifetime, allocating all
metabolic energy to a single massive reproductive event. In the light of the above statements, choose the
correct answer:
(R): Assertion (A): Bamboo and Pacific salmon fish breed many times during their lifetime to maximize
larval recruitment.
Reason (R): Most birds and mammals breed only once in their lifetime, allocating all
metabolic energy to a single massive reproductive event. In the light of the above statements, choose the
correct answer:
65.Consider the following statements regarding the reproductive allocation strategies in terms of
offspring size and number: I. Some organisms produce a large number of small-sized offspring.
II.
Examples of organisms producing large numbers of small offspring are oysters and pelagic fishes.
III.
Some organisms produce a small number of large-sized offspring.
IV. Examples of organisms producing
small numbers of large offspring are birds and mammals. Which of the statements given above are correct
according to the NCERT textbook?
offspring size and number: I. Some organisms produce a large number of small-sized offspring.
II.
Examples of organisms producing large numbers of small offspring are oysters and pelagic fishes.
III.
Some organisms produce a small number of large-sized offspring.
IV. Examples of organisms producing
small numbers of large offspring are birds and mammals. Which of the statements given above are correct
according to the NCERT textbook?
66.Given below are two statements, one is labelled as Assertion (A) and the other is labelled as Reason
(R): Assertion (A): Oysters and pelagic fishes produce a small number of large-sized offspring to
maximize post-natal survival.
Reason (R): Birds and mammals produce a large number of small-sized
offspring that float freely in the water column as plankton. In the light of the above statements, choose the
correct answer:
(R): Assertion (A): Oysters and pelagic fishes produce a small number of large-sized offspring to
maximize post-natal survival.
Reason (R): Birds and mammals produce a large number of small-sized
offspring that float freely in the water column as plankton. In the light of the above statements, choose the
correct answer:
67.Consider the following statements regarding the evolutionary drivers of life history traits in different
species: I. Under a particular set of selection pressures, organisms evolve towards the most efficient
reproductive strategy.
II. Life history traits of organisms have evolved in relation to constraints imposed
by the abiotic and biotic components of the habitat.
III. The evolution of life history traits in different
species is currently an important area of research being conducted by ecologists.
IV. The reproductive
strategies are completely independent of the constraints imposed by the biotic components of the habitat.
Which of the statements given above are correct according to the NCERT textbook?
species: I. Under a particular set of selection pressures, organisms evolve towards the most efficient
reproductive strategy.
II. Life history traits of organisms have evolved in relation to constraints imposed
by the abiotic and biotic components of the habitat.
III. The evolution of life history traits in different
species is currently an important area of research being conducted by ecologists.
IV. The reproductive
strategies are completely independent of the constraints imposed by the biotic components of the habitat.
Which of the statements given above are correct according to the NCERT textbook?
68.Given below are two statements, one is labelled as Assertion (A) and the other is labelled as Reason
(R): Assertion (A): There is no natural habitat on earth that is inhabited just by a single species.
Reason
(R): For any species, the minimal requirement is at least one more species on which it can feed. In the light
of the above statements, choose the correct answer:
(R): Assertion (A): There is no natural habitat on earth that is inhabited just by a single species.
Reason
(R): For any species, the minimal requirement is at least one more species on which it can feed. In the light
of the above statements, choose the correct answer:
69.Consider the following statements regarding the survival needs of an autotrophic plant species in a
habitat: I. Even a plant species, which makes its own food, cannot survive alone in a habitat.
II. A plant
needs soil microbes to break down organic matter in the soil and return inorganic nutrients.
III. The plant
also needs animal agents for pollination to manage reproduction.
IV. The autotrophic plant is completely
self-sufficient and requires absolutely no soil microbes or animal agents for its survival or propagation.
Which of the statements given above are correct according to the NCERT textbook?
habitat: I. Even a plant species, which makes its own food, cannot survive alone in a habitat.
II. A plant
needs soil microbes to break down organic matter in the soil and return inorganic nutrients.
III. The plant
also needs animal agents for pollination to manage reproduction.
IV. The autotrophic plant is completely
self-sufficient and requires absolutely no soil microbes or animal agents for its survival or propagation.
Which of the statements given above are correct according to the NCERT textbook?
70.Given below are two statements, one is labelled as Assertion (A) and the other is labelled as Reason
(R): Assertion (A): In nature, animals, plants, and microbes do not and cannot live in isolation but interact
in various ways to form a biological community.
Reason (R): In even the most minimal biological
communities, many interactive linkages exist, although all may not be readily apparent. In the light of the
above statements, choose the correct answer:
(R): Assertion (A): In nature, animals, plants, and microbes do not and cannot live in isolation but interact
in various ways to form a biological community.
Reason (R): In even the most minimal biological
communities, many interactive linkages exist, although all may not be readily apparent. In the light of the
above statements, choose the correct answer:
71.Consider the following statements regarding the definition and scope of interspecific interactions: I.
Interspecific interactions arise from the interaction of populations of two different species.
II. Interspecific
interactions could be beneficial, detrimental, or neutral to one of the species or both.
III. A beneficial
interaction is assigned a '+' sign, a detrimental interaction is assigned a '-' sign, and a neutral interaction
is assigned a '0' sign.
IV. Interspecific interactions strictly exclude any interactions where both species
lose. Which of the statements given above are correct according to the NCERT textbook?
Interspecific interactions arise from the interaction of populations of two different species.
II. Interspecific
interactions could be beneficial, detrimental, or neutral to one of the species or both.
III. A beneficial
interaction is assigned a '+' sign, a detrimental interaction is assigned a '-' sign, and a neutral interaction
is assigned a '0' sign.
IV. Interspecific interactions strictly exclude any interactions where both species
lose. Which of the statements given above are correct according to the NCERT textbook?
72.Given below are two statements, one is labelled as Assertion (A) and the other is labelled as Reason
(R): Assertion (A): In Mutualism, both Species A and Species B benefit, representing a (+ , +) interaction
outcome.
Reason (R): In Competition, both Species A and Species B lose, representing a (– , –) interaction
outcome.
In the light of the above statements, choose the correct answer:
(R): Assertion (A): In Mutualism, both Species A and Species B benefit, representing a (+ , +) interaction
outcome.
Reason (R): In Competition, both Species A and Species B lose, representing a (– , –) interaction
outcome.
In the light of the above statements, choose the correct answer:
73.Consider the following statements regarding the sign assignments of population interactions in Table
11.1: I. In Predation, Species A (predator) benefits (+) and Species B (prey) is harmed (-).
II. In Parasitism,
Species A (parasite) benefits (+) and Species B (host) is harmed (-).
III. In Commensalism, Species A
benefits (+) and Species B is unaffected (0).
IV. In Amensalism, Species A is harmed (-) and Species B is
unaffected (0). Which of the statements given above are correct according to the NCERT table?
11.1: I. In Predation, Species A (predator) benefits (+) and Species B (prey) is harmed (-).
II. In Parasitism,
Species A (parasite) benefits (+) and Species B (host) is harmed (-).
III. In Commensalism, Species A
benefits (+) and Species B is unaffected (0).
IV. In Amensalism, Species A is harmed (-) and Species B is
unaffected (0). Which of the statements given above are correct according to the NCERT table?
74.Given below are two statements, one is labelled as Assertion (A) and the other is labelled as Reason
(R): Assertion (A): In amensalism, one species is benefited and the other is unaffected.
Reason (R): In
commensalism, one species is harmed whereas the other is unaffected. In the light of the above statements,
choose the correct answer:
(R): Assertion (A): In amensalism, one species is benefited and the other is unaffected.
Reason (R): In
commensalism, one species is harmed whereas the other is unaffected. In the light of the above statements,
choose the correct answer:
75.According to the introductory section of population interactions, which of the following groups of
interactions share the common characteristic that the interacting species live closely together?
I.
Predation II. Parasitism III. Commensalism IV. Mutualism Choose the correct option:
interactions share the common characteristic that the interacting species live closely together?
I.
Predation II. Parasitism III. Commensalism IV. Mutualism Choose the correct option:
76.Given below are two statements, one is labelled as Assertion (A) and the other is labelled as Reason
(R): Assertion (A): You can think of predation as nature's way of transferring to higher trophic levels the
energy fixed by plants.
Reason (R): Predators act as 'conduits' for energy transfer across different trophic
levels in an ecosystem.
In the light of the above statements, choose the correct answer:
(R): Assertion (A): You can think of predation as nature's way of transferring to higher trophic levels the
energy fixed by plants.
Reason (R): Predators act as 'conduits' for energy transfer across different trophic
levels in an ecosystem.
In the light of the above statements, choose the correct answer:
77.Consider the following statements regarding the ecological categorization of predators: I. When we
think of predator and prey, most probably it is the tiger and the deer that come to mind.
II. A sparrow
eating any seed is no less a predator in a broad ecological context.
III. Animals eating plants are
categorized separately as herbivores to distinguish them from animal-eating predators.
IV. In a broad
ecological context, herbivores are very different from predators because plants do not run. Which of the
statements given above are correct according to the NCERT textbook?
think of predator and prey, most probably it is the tiger and the deer that come to mind.
II. A sparrow
eating any seed is no less a predator in a broad ecological context.
III. Animals eating plants are
categorized separately as herbivores to distinguish them from animal-eating predators.
IV. In a broad
ecological context, herbivores are very different from predators because plants do not run. Which of the
statements given above are correct according to the NCERT textbook?
78.Given below are two statements, one is labelled as Assertion (A) and the other is labelled as Reason
(R): Assertion (A): Besides acting as conduits, predators play an important role in keeping prey
populations under control.
Reason (R): But for predators, prey species could achieve very high population
densities and cause ecosystem instability.
In the light of the above statements, choose the correct answer:
(R): Assertion (A): Besides acting as conduits, predators play an important role in keeping prey
populations under control.
Reason (R): But for predators, prey species could achieve very high population
densities and cause ecosystem instability.
In the light of the above statements, choose the correct answer:
79.Consider the following statements regarding the behavior of exotic species introduced into a new
geographical area: I. When certain exotic species are introduced into a geographical area, they become
invasive.
II. Exotic species start spreading fast because the invaded land does not have its natural
predators.
III. The rapid spread of invasive species is driven by the abundant synthesis of heavy isotopes
in the host foliage.
IV. The invaded land provides an ideal habitat because there are no abiotic stress
barriers. Which of the statements given above are correct according to the NCERT textbook?
geographical area: I. When certain exotic species are introduced into a geographical area, they become
invasive.
II. Exotic species start spreading fast because the invaded land does not have its natural
predators.
III. The rapid spread of invasive species is driven by the abundant synthesis of heavy isotopes
in the host foliage.
IV. The invaded land provides an ideal habitat because there are no abiotic stress
barriers. Which of the statements given above are correct according to the NCERT textbook?
80.Given below are two statements, one is labelled as Assertion (A) and the other is labelled as Reason
(R): Assertion (A): The prickly pear cactus was introduced into Australia in the early 1920s.
Reason (R):
It caused havoc by spreading rapidly into millions of hectares of rangeland until it was brought under
control by a predatory beetle.
In the light of the above statements, choose the correct answer:
(R): Assertion (A): The prickly pear cactus was introduced into Australia in the early 1920s.
Reason (R):
It caused havoc by spreading rapidly into millions of hectares of rangeland until it was brought under
control by a predatory beetle.
In the light of the above statements, choose the correct answer:
81.Consider the following statements regarding the ecological principles underlying agricultural pest
control: I. Biological control methods adopted in agricultural pest control are based on the ability of the
predator to regulate prey population.
II. Predators help in maintaining species diversity in a community.
III. Predators maintain diversity by reducing the intensity of competition among competing prey species.
IV. Predators maintain diversity by directly feeding on the least competitive species, allowing dominant
competitors to expand. Which of the statements given above are correct according to the NCERT
textbook?
control: I. Biological control methods adopted in agricultural pest control are based on the ability of the
predator to regulate prey population.
II. Predators help in maintaining species diversity in a community.
III. Predators maintain diversity by reducing the intensity of competition among competing prey species.
IV. Predators maintain diversity by directly feeding on the least competitive species, allowing dominant
competitors to expand. Which of the statements given above are correct according to the NCERT
textbook?
82.Given below are two statements, one is labelled as Assertion (A) and the other is labelled as Reason
(R): Assertion (A): In the rocky intertidal communities of the American Pacific Coast, the starfish Pisaster
is an important predator.
Reason (R): In a field experiment, when all the starfish were removed from an
enclosed intertidal area, more than 10 species of vertebrates became extinct within a year. In the light of
the above statements, choose the correct answer:
(R): Assertion (A): In the rocky intertidal communities of the American Pacific Coast, the starfish Pisaster
is an important predator.
Reason (R): In a field experiment, when all the starfish were removed from an
enclosed intertidal area, more than 10 species of vertebrates became extinct within a year. In the light of
the above statements, choose the correct answer:
83.Consider the following statements regarding the ecological mechanism of extinction in the starfish
Pisaster removal experiment: I. The extinction occurred within a year of removing the starfish.
II. More
than 10 species became extinct in the enclosed area.
III. The extinction was a direct consequence of intense
interspecific competition.
IV. The extinction occurred because the starfish was the primary herbivore that
controlled plant populations. Which of the statements given above are correct according to the NCERT
textbook?
Pisaster removal experiment: I. The extinction occurred within a year of removing the starfish.
II. More
than 10 species became extinct in the enclosed area.
III. The extinction was a direct consequence of intense
interspecific competition.
IV. The extinction occurred because the starfish was the primary herbivore that
controlled plant populations. Which of the statements given above are correct according to the NCERT
textbook?
84.Given below are two statements, one is labelled as Assertion (A) and the other is labelled as Reason
(R): Assertion (A): Predators in nature are 'prudent' and rarely overexploit their prey to extinction.
Reason (R): If a predator is too efficient and overexploits its prey, the prey might become extinct and
following it, the predator will also become extinct for lack of food. In the light of the above statements,
choose the correct answer:
(R): Assertion (A): Predators in nature are 'prudent' and rarely overexploit their prey to extinction.
Reason (R): If a predator is too efficient and overexploits its prey, the prey might become extinct and
following it, the predator will also become extinct for lack of food. In the light of the above statements,
choose the correct answer:
85.Consider the following statements regarding the diverse defenses evolved by prey species to lessen
the impact of predation: I. Prey species have evolved various morphological and chemical defenses to
avoid detection or ingestion.
II. Some species of insects and frogs are cryptically-coloured (camouflaged)
to avoid being detected easily by predators.
III. Some prey species are poisonous and therefore avoided by
the predators.
IV. Cryptic coloration involves the secretion of heavy alkaline pigments that chemically
burn the predator's visual pathways. Which of the statements given above are correct according to the
NCERT textbook?
the impact of predation: I. Prey species have evolved various morphological and chemical defenses to
avoid detection or ingestion.
II. Some species of insects and frogs are cryptically-coloured (camouflaged)
to avoid being detected easily by predators.
III. Some prey species are poisonous and therefore avoided by
the predators.
IV. Cryptic coloration involves the secretion of heavy alkaline pigments that chemically
burn the predator's visual pathways. Which of the statements given above are correct according to the
NCERT textbook?
86.Given below are two statements, one is labelled as Assertion (A) and the other is labelled as Reason
(R): Assertion (A): The Monarch butterfly is highly distasteful to its predator bird.
Reason (R): The
butterfly synthesizes a special cardiac glycoside during its adult stage by metabolizing plant nectar. In the
light of the above statements, choose the correct answer:
(R): Assertion (A): The Monarch butterfly is highly distasteful to its predator bird.
Reason (R): The
butterfly synthesizes a special cardiac glycoside during its adult stage by metabolizing plant nectar. In the
light of the above statements, choose the correct answer:
87.Consider the following statements regarding the Monarch butterfly's defensive strategy: I. The
Monarch butterfly is distasteful specifically to its predator bird.
II. It possesses a special chemical present
in its body that confers this distastefulness.
III. The chemical is acquired during its caterpillar stage.
IV.
The source of the chemical is a poisonous weed eaten by the caterpillar. Which of the statements given
above are correct according to the NCERT textbook?
Monarch butterfly is distasteful specifically to its predator bird.
II. It possesses a special chemical present
in its body that confers this distastefulness.
III. The chemical is acquired during its caterpillar stage.
IV.
The source of the chemical is a poisonous weed eaten by the caterpillar. Which of the statements given
above are correct according to the NCERT textbook?
88.Given below are two statements, one is labelled as Assertion (A) and the other is labelled as Reason
(R): Assertion (A): The problem of predation is particularly severe for plants compared to animals.
Reason (R): Unlike animals, plants cannot run away from their predators. In the light of the above
statements, choose the correct answer:
(R): Assertion (A): The problem of predation is particularly severe for plants compared to animals.
Reason (R): Unlike animals, plants cannot run away from their predators. In the light of the above
statements, choose the correct answer:
89.Consider the following statements regarding herbivory as a form of predation: I. For plants,
herbivores are the predators.
II. Nearly 25 per cent of all insects are known to be phytophagous.
III.
Phytophagous insects are defined as those feeding on plant sap and other parts of plants.
IV. Plants have
evolved an astonishing variety of morphological and chemical defences against herbivores. Which of the
statements given above are correct according to the NCERT textbook?
herbivores are the predators.
II. Nearly 25 per cent of all insects are known to be phytophagous.
III.
Phytophagous insects are defined as those feeding on plant sap and other parts of plants.
IV. Plants have
evolved an astonishing variety of morphological and chemical defences against herbivores. Which of the
statements given above are correct according to the NCERT textbook?
90.Given below are two statements, one is labelled as Assertion (A) and the other is labelled as Reason
(R): Assertion (A): Nearly 50 per cent of all insects are known to be phytophagous, feeding strictly on
xylem vessels.
Reason (R): Phytophagous insects represent a major class of primary producers in forest
ecosystems.
In the light of the above statements, choose the correct answer:
(R): Assertion (A): Nearly 50 per cent of all insects are known to be phytophagous, feeding strictly on
xylem vessels.
Reason (R): Phytophagous insects represent a major class of primary producers in forest
ecosystems.
In the light of the above statements, choose the correct answer:
91.Consider the following statements regarding the morphological defenses evolved by plants against
herbivores: I. Thorns are the most common morphological means of defense.
II. Examples of plants
possessing thorns for defense are Acacia and Cactus.
III. Spines in Cactus are morphologically identical to
the thorns of Acacia.
IV. Thorns act by chemically secreting highly sticky lipids that glue the herbivore's
mouthparts. Which of the statements given above are correct according to the NCERT textbook?
herbivores: I. Thorns are the most common morphological means of defense.
II. Examples of plants
possessing thorns for defense are Acacia and Cactus.
III. Spines in Cactus are morphologically identical to
the thorns of Acacia.
IV. Thorns act by chemically secreting highly sticky lipids that glue the herbivore's
mouthparts. Which of the statements given above are correct according to the NCERT textbook?
92.Given below are two statements, one is labelled as Assertion (A) and the other is labelled as Reason
(R): Assertion (A): Thorns represent the most common morphological defense mechanism in Acacia and
Cactus.
Reason (R): These morphological barriers are highly effective because they are coupled with the
secretion of toxic latex in both species.
In the light of the above statements, choose the correct answer:
(R): Assertion (A): Thorns represent the most common morphological defense mechanism in Acacia and
Cactus.
Reason (R): These morphological barriers are highly effective because they are coupled with the
secretion of toxic latex in both species.
In the light of the above statements, choose the correct answer:
93.Consider the following statements regarding the diverse physiological effects of chemical substances
produced by plants as defenses against herbivores: I. Many plants produce and store chemicals that make
the herbivore sick when they are eaten.
II. Some chemicals inhibit feeding or digestion in the herbivore.
III. Certain chemicals disrupt the reproduction of the grazing or browsing animal.
IV. Some chemicals can
directly kill the herbivore. Which of the statements given above are correct according to the NCERT
textbook?
produced by plants as defenses against herbivores: I. Many plants produce and store chemicals that make
the herbivore sick when they are eaten.
II. Some chemicals inhibit feeding or digestion in the herbivore.
III. Certain chemicals disrupt the reproduction of the grazing or browsing animal.
IV. Some chemicals can
directly kill the herbivore. Which of the statements given above are correct according to the NCERT
textbook?
94.Given below are two statements, one is labelled as Assertion (A) and the other is labelled as Reason
(R): Assertion (A): Chemical defenses in plants are designed strictly to stimulate feeding and accelerate
digestion in herbivores.
Reason (R): This stimulation makes the herbivore overeat and eventually die of
abdominal rupture.
In the light of the above statements, choose the correct answer:
(R): Assertion (A): Chemical defenses in plants are designed strictly to stimulate feeding and accelerate
digestion in herbivores.
Reason (R): This stimulation makes the herbivore overeat and eventually die of
abdominal rupture.
In the light of the above statements, choose the correct answer:
95.Consider the following statements regarding the defensive strategy of the weed Calotropis: I.
Calotropis is a weed that grows in abandoned fields.
II. The plant produces highly poisonous cardiac
glycosides.
III. Because of these glycosides, you never see any cattle or goats browsing on this plant.
IV.
Calotropis is described as a highly valued forage plant imported to feed livestock. Which of the statements
given above are correct according to the NCERT textbook?
Calotropis is a weed that grows in abandoned fields.
II. The plant produces highly poisonous cardiac
glycosides.
III. Because of these glycosides, you never see any cattle or goats browsing on this plant.
IV.
Calotropis is described as a highly valued forage plant imported to feed livestock. Which of the statements
given above are correct according to the NCERT textbook?
96.Given below are two statements, one is labelled as Assertion (A) and the other is labelled as Reason
(R): Assertion (A): The weed Calotropis produces highly poisonous cardiac glycosides in its foliage.
Reason (R): These glycosides are chemically classified as alkaloids that stimulate the heart rate of cattle
and goats to hyperactive levels.
In the light of the above statements, choose the correct answer:
(R): Assertion (A): The weed Calotropis produces highly poisonous cardiac glycosides in its foliage.
Reason (R): These glycosides are chemically classified as alkaloids that stimulate the heart rate of cattle
and goats to hyperactive levels.
In the light of the above statements, choose the correct answer:
97.According to the NCERT textbook, plants produce a wide variety of chemical substances that we
extract on a commercial scale. Which of the following is the correct, complete list of these commercial
chemicals explicitly printed in the text as plant defenses against grazers and browsers?
I. Nicotine,
caffeine.
II. Quinine, strychnine.
III. Opium.
IV. Reserpine, atropine, cocaine. Choose the correct option:
extract on a commercial scale. Which of the following is the correct, complete list of these commercial
chemicals explicitly printed in the text as plant defenses against grazers and browsers?
I. Nicotine,
caffeine.
II. Quinine, strychnine.
III. Opium.
IV. Reserpine, atropine, cocaine. Choose the correct option:
98.Given below are two statements, one is labelled as Assertion (A) and the other is labelled as Reason
(R): Assertion (A): Nicotine, caffeine, quinine, strychnine, and opium are extracted from plants on a
commercial scale by humans.
Reason (R): These chemical substances are produced by the plants actually
as primary metabolic precursors for starch synthesis. In the light of the above statements, choose the
correct answer:
(R): Assertion (A): Nicotine, caffeine, quinine, strychnine, and opium are extracted from plants on a
commercial scale by humans.
Reason (R): These chemical substances are produced by the plants actually
as primary metabolic precursors for starch synthesis. In the light of the above statements, choose the
correct answer:
99.Consider the following statements regarding the role of competition in organic evolution as described
in Section 11.1.4 (ii): I. When Darwin spoke of the struggle for existence and survival of the fittest, he was
convinced of the role of competition.
II. Darwin was convinced that interspecific competition is a potent
force in organic evolution.
III. Darwin was convinced that intraspecific competition is the only valid driver
of organic evolution, while interspecific competition is neutral.
IV. Interspecific competition arises strictly
between totally identical chromosomal variants of the same species. Which of the statements given above
are correct according to the NCERT textbook?
in Section 11.1.4 (ii): I. When Darwin spoke of the struggle for existence and survival of the fittest, he was
convinced of the role of competition.
II. Darwin was convinced that interspecific competition is a potent
force in organic evolution.
III. Darwin was convinced that intraspecific competition is the only valid driver
of organic evolution, while interspecific competition is neutral.
IV. Interspecific competition arises strictly
between totally identical chromosomal variants of the same species. Which of the statements given above
are correct according to the NCERT textbook?
100.Given below are two statements, one is labelled as Assertion (A) and the other is labelled as Reason
(R): Assertion (A): It is generally believed that competition occurs when closely related species compete
for the same resources that are limiting.
Reason (R): Extensive ecological studies have proved that this
general belief is completely and entirely true in all natural scenarios without exception. In the light of the
above statements, choose the correct answer:
(R): Assertion (A): It is generally believed that competition occurs when closely related species compete
for the same resources that are limiting.
Reason (R): Extensive ecological studies have proved that this
general belief is completely and entirely true in all natural scenarios without exception. In the light of the
above statements, choose the correct answer:
101.Consider the following statements regarding the competition between totally unrelated species: I.
Totally unrelated species could compete for the same resource.
II. An example is shallow South American
lakes, where visiting flamingoes and resident fishes compete.
III. The common resource for which the
flamingoes and fishes compete is the zooplankton in the lake.
IV. The flamingoes and fishes compete
because they represent closely related ancestral lineages. Which of the statements given above are correct
according to the NCERT textbook?
Totally unrelated species could compete for the same resource.
II. An example is shallow South American
lakes, where visiting flamingoes and resident fishes compete.
III. The common resource for which the
flamingoes and fishes compete is the zooplankton in the lake.
IV. The flamingoes and fishes compete
because they represent closely related ancestral lineages. Which of the statements given above are correct
according to the NCERT textbook?
102.Given below are two statements, one is labelled as Assertion (A) and the other is labelled as Reason
(R): Assertion (A): Visiting flamingoes and resident fishes compete in shallow North American lakes.
Reason (R): They compete for their common food, which is the phytoplankton suspended in the pelagic
zone.
In the light of the above statements, choose the correct answer:
(R): Assertion (A): Visiting flamingoes and resident fishes compete in shallow North American lakes.
Reason (R): They compete for their common food, which is the phytoplankton suspended in the pelagic
zone.
In the light of the above statements, choose the correct answer:
103.Consider the following statements regarding the dynamics of competition when resources are
abundant: I. Resources need not be limiting for competition to occur.
II. In interference competition, the
feeding efficiency of one species might be reduced due to the interfering presence of the other.
III.
Interference competition can occur even if resources (food and space) are abundant.
IV. In interference
competition, the species always divide the resource equally without any reduction in individual fitness.
Which of the statements given above are correct according to the NCERT textbook?
abundant: I. Resources need not be limiting for competition to occur.
II. In interference competition, the
feeding efficiency of one species might be reduced due to the interfering presence of the other.
III.
Interference competition can occur even if resources (food and space) are abundant.
IV. In interference
competition, the species always divide the resource equally without any reduction in individual fitness.
Which of the statements given above are correct according to the NCERT textbook?
104.Given below are two statements, one is labelled as Assertion (A) and the other is labelled as Reason
(R): Assertion (A): Competition is best defined as a process in which the fitness of one species is
significantly lower in the presence of another species.
Reason (R): The biological fitness of a species in
competition is technically measured in terms of its 'r', the intrinsic rate of increase. In the light of the
above statements, choose the correct answer:
(R): Assertion (A): Competition is best defined as a process in which the fitness of one species is
significantly lower in the presence of another species.
Reason (R): The biological fitness of a species in
competition is technically measured in terms of its 'r', the intrinsic rate of increase. In the light of the
above statements, choose the correct answer:
105.Consider the following statements regarding the experimental and natural evidence for competitive
exclusion: I. Laboratory experiments easily demonstrate that competitively superior species eventually
eliminate other species.
II. Gause and other experimental ecologists conducted these laboratory
demonstrations when resources were limited.
III. Evidence for competitive exclusion occurring in nature
is always absolute, direct, and universally conclusive.
IV. Strong and persuasive circumstantial evidence
does exist for competitive exclusion in some natural cases. Which of the statements given above are correct
according to the NCERT textbook?
exclusion: I. Laboratory experiments easily demonstrate that competitively superior species eventually
eliminate other species.
II. Gause and other experimental ecologists conducted these laboratory
demonstrations when resources were limited.
III. Evidence for competitive exclusion occurring in nature
is always absolute, direct, and universally conclusive.
IV. Strong and persuasive circumstantial evidence
does exist for competitive exclusion in some natural cases. Which of the statements given above are correct
according to the NCERT textbook?
106.Given below are two statements, one is labelled as Assertion (A) and the other is labelled as Reason
(R): Assertion (A): The Abingdon tortoise in the Galapagos Islands became extinct within a decade after
goats were introduced on the island.
Reason (R): The extinction occurred apparently due to the greater
browsing efficiency of the goats.
In the light of the above statements, choose the correct answer:
(R): Assertion (A): The Abingdon tortoise in the Galapagos Islands became extinct within a decade after
goats were introduced on the island.
Reason (R): The extinction occurred apparently due to the greater
browsing efficiency of the goats.
In the light of the above statements, choose the correct answer:
107.Consider the following statements regarding the Abingdon tortoise competitive exclusion case
study: I. The tortoise went extinct on the Hawaii islands.
II. The tortoise went extinct within a year of
introducing goats.
III. The introduced competitor was the feral pig.
IV. The extinction occurred within a
decade on the Galapagos Islands after goats were introduced. Which of the statements given above is/are
correct according to the NCERT textbook?
study: I. The tortoise went extinct on the Hawaii islands.
II. The tortoise went extinct within a year of
introducing goats.
III. The introduced competitor was the feral pig.
IV. The extinction occurred within a
decade on the Galapagos Islands after goats were introduced. Which of the statements given above is/are
correct according to the NCERT textbook?
108.Given below are two statements, one is labelled as Assertion (A) and the other is labelled as Reason
(R): Assertion (A): A species whose distribution is restricted to a small area expands its distributional
range dramatically when the competing species is experimentally removed.
Reason (R): This dramatic
expansion of distributional range upon competitor removal is called 'competitive release'. In the light of
the above statements, choose the correct answer:
(R): Assertion (A): A species whose distribution is restricted to a small area expands its distributional
range dramatically when the competing species is experimentally removed.
Reason (R): This dramatic
expansion of distributional range upon competitor removal is called 'competitive release'. In the light of
the above statements, choose the correct answer:
109.Consider the following statements regarding Connell's field experiments on the sea coasts of
Scotland: I. The experiments were conducted on the rocky sea coasts of Scotland.
II. The larger and
competitively superior barnacle Balanus dominates the intertidal area.
III. Balanus excludes the smaller
barnacle Chathamalus from the intertidal zone.
IV. Chathamalus was experimentally shown to be
competitively superior to Balanus under high-tide conditions. Which of the statements given above are
correct according to the NCERT textbook?
Scotland: I. The experiments were conducted on the rocky sea coasts of Scotland.
II. The larger and
competitively superior barnacle Balanus dominates the intertidal area.
III. Balanus excludes the smaller
barnacle Chathamalus from the intertidal zone.
IV. Chathamalus was experimentally shown to be
competitively superior to Balanus under high-tide conditions. Which of the statements given above are
correct according to the NCERT textbook?
110.Given below are two statements, one is labelled as Assertion (A) and the other is labelled as Reason
(R): Assertion (A): The larger and competitively superior barnacle Chathamalus dominates the rocky
intertidal zone of Scotland.
Reason (R): It excludes the smaller and inferior barnacle Balanus from that
zone, driving it to deep benthic channels.
In the light of the above statements, choose the correct answer:
(R): Assertion (A): The larger and competitively superior barnacle Chathamalus dominates the rocky
intertidal zone of Scotland.
Reason (R): It excludes the smaller and inferior barnacle Balanus from that
zone, driving it to deep benthic channels.
In the light of the above statements, choose the correct answer:
111.According to the NCERT textbook, which of the following statements regarding the general
sensitivity of different trophic guilds to competition are correct?
I. In general, herbivores and plants
appear to be more adversely affected by competition than carnivores.
II. Carnivores are always more
severely impacted by competition than herbivores due to energy constraints in food webs.
III. Plants
appear to be completely immune to competitive exclusion in natural forests.
IV. In general, herbivores are
more adversely affected by competition than plants. Which of the statements given above is/are correct
according to the NCERT textbook?
sensitivity of different trophic guilds to competition are correct?
I. In general, herbivores and plants
appear to be more adversely affected by competition than carnivores.
II. Carnivores are always more
severely impacted by competition than herbivores due to energy constraints in food webs.
III. Plants
appear to be completely immune to competitive exclusion in natural forests.
IV. In general, herbivores are
more adversely affected by competition than plants. Which of the statements given above is/are correct
according to the NCERT textbook?
112.Given below are two statements, one is labelled as Assertion (A) and the other is labelled as Reason
(R): Assertion (A): Gause's 'Competitive Exclusion Principle' states that two closely related species
competing for the same resources cannot co-exist indefinitely.
Reason (R): Under limited resource
conditions, the competitively superior species will eventually eliminate the competitively inferior one. In
the light of the above statements, choose the correct answer:
(R): Assertion (A): Gause's 'Competitive Exclusion Principle' states that two closely related species
competing for the same resources cannot co-exist indefinitely.
Reason (R): Under limited resource
conditions, the competitively superior species will eventually eliminate the competitively inferior one. In
the light of the above statements, choose the correct answer:
113.Consider the following statements regarding the modern scientific limitations and updates to
Gause's Exclusion Principle: I. Gause's principle may be true if resources are limiting, but not otherwise.
II. More recent studies do not support gross generalisations about competition.
III. Recent studies point
out that species facing competition might evolve mechanisms that promote co-existence rather than
exclusion.
IV. Recent studies have completely ruled out the occurrence of interspecific competition in
nature under any circumstance. Which of the statements given above are correct according to the NCERT
textbook?
Gause's Exclusion Principle: I. Gause's principle may be true if resources are limiting, but not otherwise.
II. More recent studies do not support gross generalisations about competition.
III. Recent studies point
out that species facing competition might evolve mechanisms that promote co-existence rather than
exclusion.
IV. Recent studies have completely ruled out the occurrence of interspecific competition in
nature under any circumstance. Which of the statements given above are correct according to the NCERT
textbook?
114.Given below are two statements, one is labelled as Assertion (A) and the other is labelled as Reason
(R): Assertion (A): Resource partitioning is a primary mechanism that promotes species co-existence
rather than competitive exclusion.
Reason (R): If two species compete for the same resource, they could
avoid competition by choosing different times for feeding or different foraging patterns. In the light of the
above statements, choose the correct answer:
(R): Assertion (A): Resource partitioning is a primary mechanism that promotes species co-existence
rather than competitive exclusion.
Reason (R): If two species compete for the same resource, they could
avoid competition by choosing different times for feeding or different foraging patterns. In the light of the
above statements, choose the correct answer:
115.Consider the following statements regarding MacArthur's landmark study on co-existing warblers:
I. MacArthur showed that five closely related species of warblers co-existed on the same tree.
II. The
warblers were able to avoid competition and co-exist due to behavioural differences in their foraging
activities.
III. The warblers co-existed by feeding on completely distinct trophic levels, such as leaves and
avian eggs.
IV. The number of closely related warbler species in the study was exactly three. Which of the
statements given above are correct according to the NCERT textbook?
I. MacArthur showed that five closely related species of warblers co-existed on the same tree.
II. The
warblers were able to avoid competition and co-exist due to behavioural differences in their foraging
activities.
III. The warblers co-existed by feeding on completely distinct trophic levels, such as leaves and
avian eggs.
IV. The number of closely related warbler species in the study was exactly three. Which of the
statements given above are correct according to the NCERT textbook?
116.Given below are two statements, one is labelled as Assertion (A) and the other is labelled as Reason
(R): Assertion (A): MacArthur's elegant study proved that five closely related species of warblers avoid
competitive exclusion on a single tree.
Reason (R): These five species represent distinct taxonomic orders
that evolved in completely separate continental geographic biomes. In the light of the above statements,
choose the correct answer:
(R): Assertion (A): MacArthur's elegant study proved that five closely related species of warblers avoid
competitive exclusion on a single tree.
Reason (R): These five species represent distinct taxonomic orders
that evolved in completely separate continental geographic biomes. In the light of the above statements,
choose the correct answer:
117.Consider the following statements regarding the evolutionary characteristics of a parasitic mode of
life: I. Parasitism ensures free lodging and meals for the parasite.
II. Parasitism has evolved in many
taxonomic groups from plants to higher vertebrates.
III. Many parasites have evolved to be highly host-
specific (parasitising only a single species of host).
IV. Host-specificity ensures that both the host and the
parasite tend to co-evolve. Which of the statements given above are correct according to the NCERT
textbook?
life: I. Parasitism ensures free lodging and meals for the parasite.
II. Parasitism has evolved in many
taxonomic groups from plants to higher vertebrates.
III. Many parasites have evolved to be highly host-
specific (parasitising only a single species of host).
IV. Host-specificity ensures that both the host and the
parasite tend to co-evolve. Which of the statements given above are correct according to the NCERT
textbook?
118.Given below are two statements, one is labelled as Assertion (A) and the other is labelled as Reason
(R): Assertion (A): Parasites have evolved special adaptations like loss of unnecessary sense organs and
high reproductive capacity.
Reason (R): These adaptations are evolved in accordance with their lifestyles
to successfully exploit the host's body and guarantee offspring survival. In the light of the above
statements, choose the correct answer:
(R): Assertion (A): Parasites have evolved special adaptations like loss of unnecessary sense organs and
high reproductive capacity.
Reason (R): These adaptations are evolved in accordance with their lifestyles
to successfully exploit the host's body and guarantee offspring survival. In the light of the above
statements, choose the correct answer:
119.According to Section 11.1.4 (iii), which of the following are explicitly listed in the text as special
adaptations evolved by parasites in accordance with their lifestyles?
I. Loss of unnecessary sense organs.
II. Presence of adhesive organs or suckers to cling on to the host.
III. Loss of digestive system.
IV. High
reproductive capacity. Choose the correct option:
adaptations evolved by parasites in accordance with their lifestyles?
I. Loss of unnecessary sense organs.
II. Presence of adhesive organs or suckers to cling on to the host.
III. Loss of digestive system.
IV. High
reproductive capacity. Choose the correct option:
120.Given below are two statements, one is labelled as Assertion (A) and the other is labelled as Reason
(R): Assertion (A): Parasites have evolved specialized adaptations such as the hyper-development of
unnecessary sense organs to actively navigate outside host matrices.
Reason (R): They also evolve a
complete loss of reproductive capacity to conserve metabolic energy inside the host's sterile digestive tract.
In the light of the above statements, choose the correct answer:
(R): Assertion (A): Parasites have evolved specialized adaptations such as the hyper-development of
unnecessary sense organs to actively navigate outside host matrices.
Reason (R): They also evolve a
complete loss of reproductive capacity to conserve metabolic energy inside the host's sterile digestive tract.
In the light of the above statements, choose the correct answer:
121.Consider the following statements regarding the complex life cycle of the human liver fluke: I. The
human liver fluke is a trematode parasite.
II. Its life cycle is complex and depends on two intermediate
hosts to complete.
III. The two intermediate hosts are a snail and a fish.
IV. The primary host of the liver
fluke is explicitly described in the text as the human liver. Which of the statements given above are correct
according to the NCERT textbook?
human liver fluke is a trematode parasite.
II. Its life cycle is complex and depends on two intermediate
hosts to complete.
III. The two intermediate hosts are a snail and a fish.
IV. The primary host of the liver
fluke is explicitly described in the text as the human liver. Which of the statements given above are correct
according to the NCERT textbook?
122.Given below are two statements, one is labelled as Assertion (A) and the other is labelled as Reason
(R): Assertion (A): The human liver fluke depends on two intermediate hosts, which are a mosquito and a
snail.
Reason (R): The malarial parasite depends on a fish vector to facilitate transmission to its primary
human host.
In the light of the above statements, choose the correct answer:
(R): Assertion (A): The human liver fluke depends on two intermediate hosts, which are a mosquito and a
snail.
Reason (R): The malarial parasite depends on a fish vector to facilitate transmission to its primary
human host.
In the light of the above statements, choose the correct answer:
123.Consider the following statements regarding the biological impacts of parasites on their hosts: I. A
majority of parasites harm the host.
II. Parasites may reduce the survival, growth, and reproduction of
the host.
III. Parasites reduce the population density of the host species.
IV. Parasites render the host more
vulnerable to predation by making it physically weak. Which of the statements given above are correct
according to the NCERT textbook?
majority of parasites harm the host.
II. Parasites may reduce the survival, growth, and reproduction of
the host.
III. Parasites reduce the population density of the host species.
IV. Parasites render the host more
vulnerable to predation by making it physically weak. Which of the statements given above are correct
according to the NCERT textbook?
124.Given below are two statements, one is labelled as Assertion (A) and the other is labelled as Reason
(R): Assertion (A): Parasites might render the host organism more vulnerable to predation.
Reason (R):
By feeding on internal tissues, parasites make the host physically weak. In the light of the above
statements, choose the correct answer:
(R): Assertion (A): Parasites might render the host organism more vulnerable to predation.
Reason (R):
By feeding on internal tissues, parasites make the host physically weak. In the light of the above
statements, choose the correct answer:
125.Consider the following statements regarding the evolutionary questions raised in Section 11.1.4 (iii):
I. The text asks whether an ideal parasite should be able to thrive within the host without harming it.
II.
The text asks why natural selection did not lead to the evolution of such totally harmless parasites.
III.
The text answers that natural selection has completely prohibited harmless parasites because they are
metabolically inefficient.
IV. The text suggests that harmless parasites do not exist because hosts always
synthesize active antibodies that kill them. Which of the statements given above are correct according to
the NCERT textbook?
I. The text asks whether an ideal parasite should be able to thrive within the host without harming it.
II.
The text asks why natural selection did not lead to the evolution of such totally harmless parasites.
III.
The text answers that natural selection has completely prohibited harmless parasites because they are
metabolically inefficient.
IV. The text suggests that harmless parasites do not exist because hosts always
synthesize active antibodies that kill them. Which of the statements given above are correct according to
the NCERT textbook?
126.Given below are two statements, one is labelled as Assertion (A) and the other is labelled as Reason
(R): Assertion (A): Parasites that feed on the external surface of the host organism are called
ectoparasites.
Reason (R): Lice on humans and ticks on dogs represent familiar examples of this group. In
the light of the above statements, choose the correct answer:
(R): Assertion (A): Parasites that feed on the external surface of the host organism are called
ectoparasites.
Reason (R): Lice on humans and ticks on dogs represent familiar examples of this group. In
the light of the above statements, choose the correct answer:
127.Consider the following statements regarding the parasitic infestations in marine ecosystems: I.
Many marine fish are infested with ectoparasitic copepods.
II. Copepods represent a group of parasitic
vascular plants that have lost their chlorophyll.
III. The ectoparasitic copepods feed on the external
surface of marine fish.
IV. Copepods are described in the text as endoparasites that destroy the gills of
marine fish. Which of the statements given above are correct according to the NCERT textbook?
Many marine fish are infested with ectoparasitic copepods.
II. Copepods represent a group of parasitic
vascular plants that have lost their chlorophyll.
III. The ectoparasitic copepods feed on the external
surface of marine fish.
IV. Copepods are described in the text as endoparasites that destroy the gills of
marine fish. Which of the statements given above are correct according to the NCERT textbook?
128.Given below are two statements, one is labelled as Assertion (A) and the other is labelled as Reason
(R): Assertion (A): Cuscuta is a parasitic plant commonly found growing on hedge plants.
Reason (R):
During its evolution, Cuscuta has completely lost its chlorophyll and leaves, deriving its nutrition from the
host plant.
In the light of the above statements, choose the correct answer:
(R): Assertion (A): Cuscuta is a parasitic plant commonly found growing on hedge plants.
Reason (R):
During its evolution, Cuscuta has completely lost its chlorophyll and leaves, deriving its nutrition from the
host plant.
In the light of the above statements, choose the correct answer:
129.Consider the following statements regarding the female mosquito's relationship with humans: I.
The female mosquito is not considered a parasite, although it needs our blood for reproduction.
II. The
female mosquito needs human blood as a direct nutrient source to sustain its own metabolic respiration.
III. The female mosquito needs blood specifically for reproduction (e.g., egg development).
IV. The female
mosquito is classified as a classic ectoparasite in Chapter 11. Which of the statements given above are
correct according to the NCERT textbook?
The female mosquito is not considered a parasite, although it needs our blood for reproduction.
II. The
female mosquito needs human blood as a direct nutrient source to sustain its own metabolic respiration.
III. The female mosquito needs blood specifically for reproduction (e.g., egg development).
IV. The female
mosquito is classified as a classic ectoparasite in Chapter 11. Which of the statements given above are
correct according to the NCERT textbook?
130.Given below are two statements, one is labelled as Assertion (A) and the other is labelled as Reason
(R): Assertion (A): The life cycles of endoparasites are generally more complex than those of ectoparasites.
Reason (R): Endoparasites live inside the host body at different sites (liver, kidney, lungs, red blood cells,
etc.) and exhibit extreme specialisation.
In the light of the above statements, choose the correct answer:
(R): Assertion (A): The life cycles of endoparasites are generally more complex than those of ectoparasites.
Reason (R): Endoparasites live inside the host body at different sites (liver, kidney, lungs, red blood cells,
etc.) and exhibit extreme specialisation.
In the light of the above statements, choose the correct answer:
131.Consider the following statements regarding the morphological and anatomical features of
endoparasites: I. Their morphological and anatomical features are greatly simplified.
II. Their
reproductive potential is highly emphasized.
III. Their digestive and sensory systems are highly developed
to actively resist the host's immune cells.
IV. The anatomical features are simplified because they live in a
highly protected, nutrient-rich environment. Which of the statements given above are correct according to
the NCERT textbook?
endoparasites: I. Their morphological and anatomical features are greatly simplified.
II. Their
reproductive potential is highly emphasized.
III. Their digestive and sensory systems are highly developed
to actively resist the host's immune cells.
IV. The anatomical features are simplified because they live in a
highly protected, nutrient-rich environment. Which of the statements given above are correct according to
the NCERT textbook?
132.Given below are two statements, one is labelled as Assertion (A) and the other is labelled as Reason
(R): Assertion (A): Brood parasitism in birds is a fascinating example of parasitism.
Reason (R): The
parasitic bird lays its eggs in the nest of its host and lets the host incubate them. In the light of the above
statements, choose the correct answer:
(R): Assertion (A): Brood parasitism in birds is a fascinating example of parasitism.
Reason (R): The
parasitic bird lays its eggs in the nest of its host and lets the host incubate them. In the light of the above
statements, choose the correct answer:
133.Consider the following statements regarding the evolutionary adaptations of eggs in brood
parasitism: I. During evolution, the eggs of the parasitic bird have evolved to resemble the host's egg in
size and color.
II. This resemblance reduces the chances of the host bird detecting the foreign eggs and
ejecting them from the nest.
III. The parasitic eggs have evolved to secrete pheromones that chemically
sedate the host bird.
IV. The host eggs always evolve to double in size when a parasitic egg is introduced.
Which of the statements given above are correct according to the NCERT textbook?
parasitism: I. During evolution, the eggs of the parasitic bird have evolved to resemble the host's egg in
size and color.
II. This resemblance reduces the chances of the host bird detecting the foreign eggs and
ejecting them from the nest.
III. The parasitic eggs have evolved to secrete pheromones that chemically
sedate the host bird.
IV. The host eggs always evolve to double in size when a parasitic egg is introduced.
Which of the statements given above are correct according to the NCERT textbook?
134.Given below are two statements, one is labelled as Assertion (A) and the other is labelled as Reason
(R): Assertion (A): Brood parasitism can be observed in action in a neighborhood park during the
breeding season from spring to summer.
Reason (R): The classic species involved in this interaction are
the cuckoo (koel) and the crow.
In the light of the above statements, choose the correct answer:
(R): Assertion (A): Brood parasitism can be observed in action in a neighborhood park during the
breeding season from spring to summer.
Reason (R): The classic species involved in this interaction are
the cuckoo (koel) and the crow.
In the light of the above statements, choose the correct answer:
135.Consider the following statements regarding the species involved in brood parasitism in India: I.
The parasitic bird is the crow, which lays its eggs in the nest of the cuckoo (koel).
II. The host bird is the
cuckoo (koel), which incubates the crow's eggs.
III. The parasitic bird is the cuckoo (koel), which lays its
eggs in the nest of the crow.
IV. The breeding season in which this occurs is winter to spring. Which of the
statements given above is/are correct according to the NCERT textbook?
The parasitic bird is the crow, which lays its eggs in the nest of the cuckoo (koel).
II. The host bird is the
cuckoo (koel), which incubates the crow's eggs.
III. The parasitic bird is the cuckoo (koel), which lays its
eggs in the nest of the crow.
IV. The breeding season in which this occurs is winter to spring. Which of the
statements given above is/are correct according to the NCERT textbook?
136.Given below are two statements, one is labelled as Assertion (A) and the other is labelled as Reason
(R): Assertion (A): Commensalism represents a unique interspecific interaction where one species benefits
while the other is unaffected.
Reason (R): In Table 11.1, the outcome matrix for commensalism is
technically designated as a (+ , 0) interaction. In the light of the above statements, choose the correct
answer:
(R): Assertion (A): Commensalism represents a unique interspecific interaction where one species benefits
while the other is unaffected.
Reason (R): In Table 11.1, the outcome matrix for commensalism is
technically designated as a (+ , 0) interaction. In the light of the above statements, choose the correct
answer:
137.Consider the following statements regarding the plant and animal examples of commensalism
described in Section 11.1.4 (iv): I. An orchid grows as an epiphyte on a mango branch.
II. Barnacles grow
on the back of a whale.
III. The orchid and the barnacles derive benefit, while the mango tree and the
whale are unaffected.
IV. The orchid is described as a parasite that sucks nutrition from the vascular
cambium of the mango branch. Which of the statements given above are correct according to the NCERT
textbook?
described in Section 11.1.4 (iv): I. An orchid grows as an epiphyte on a mango branch.
II. Barnacles grow
on the back of a whale.
III. The orchid and the barnacles derive benefit, while the mango tree and the
whale are unaffected.
IV. The orchid is described as a parasite that sucks nutrition from the vascular
cambium of the mango branch. Which of the statements given above are correct according to the NCERT
textbook?
138.Given below are two statements, one is labelled as Assertion (A) and the other is labelled as Reason
(R): Assertion (A): A barnacle growing as an epiphyte on a mango branch and an orchid growing on the
back of a whale represent commensalism.
Reason (R): The mango tree and the whale are severely harmed
by the metabolic load of these epiphytic invaders. In the light of the above statements, choose the correct
answer:
(R): Assertion (A): A barnacle growing as an epiphyte on a mango branch and an orchid growing on the
back of a whale represent commensalism.
Reason (R): The mango tree and the whale are severely harmed
by the metabolic load of these epiphytic invaders. In the light of the above statements, choose the correct
answer:
139.Consider the following statements regarding the cattle egret and grazing cattle association: I. It
represents a classic example of commensalism.
II. Egrets always forage close to where the cattle are
grazing.
III. The moving cattle stir up and flush out insects from the vegetation that otherwise would be
difficult for egrets to catch.
IV. The cattle derive a major nutritional benefit by feeding on the feathers and
ectoparasites of the egrets. Which of the statements given above are correct according to the NCERT
textbook?
represents a classic example of commensalism.
II. Egrets always forage close to where the cattle are
grazing.
III. The moving cattle stir up and flush out insects from the vegetation that otherwise would be
difficult for egrets to catch.
IV. The cattle derive a major nutritional benefit by feeding on the feathers and
ectoparasites of the egrets. Which of the statements given above are correct according to the NCERT
textbook?
140.Given below are two statements, one is labelled as Assertion (A) and the other is labelled as Reason
(R): Assertion (A): The clown fish gets protection from predators by living among the stinging tentacles of
the sea anemone.
Reason (R): The stinging tentacles of the sea anemone physically paralyze and consume
the clown fish to supply amino acids to its basal disc. In the light of the above statements, choose the
correct answer:
(R): Assertion (A): The clown fish gets protection from predators by living among the stinging tentacles of
the sea anemone.
Reason (R): The stinging tentacles of the sea anemone physically paralyze and consume
the clown fish to supply amino acids to its basal disc. In the light of the above statements, choose the
correct answer:
141.Consider the following statements regarding the definition and technical notation of mutualism: I.
Mutualism is an interspecific interaction that confers benefits on both the interacting species.
II. In Table
11.1, the outcome matrix for mutualism is designated as a (+ , +) interaction.
III. The two species in
mutualism both suffer a metabolic cost that reduces their individual intrinsic rate of increase r.
IV.
Mutualism is described in the text as a highly unstable evolutionary transient that rapidly resolves into
parasitism. Which of the statements given above are correct according to the NCERT textbook?
Mutualism is an interspecific interaction that confers benefits on both the interacting species.
II. In Table
11.1, the outcome matrix for mutualism is designated as a (+ , +) interaction.
III. The two species in
mutualism both suffer a metabolic cost that reduces their individual intrinsic rate of increase r.
IV.
Mutualism is described in the text as a highly unstable evolutionary transient that rapidly resolves into
parasitism. Which of the statements given above are correct according to the NCERT textbook?
142.Given below are two statements, one is labelled as Assertion (A) and the other is labelled as Reason
(R): Assertion (A): Lichens represent an intimate mutualistic relationship between a fungus and
photosynthesising algae or cyanobacteria.
Reason (R): The fungus provides energy-yielding carbohydrates
to the algae, while the algae helps the fungus absorb essential nutrients. In the light of the above
statements, choose the correct answer:
(R): Assertion (A): Lichens represent an intimate mutualistic relationship between a fungus and
photosynthesising algae or cyanobacteria.
Reason (R): The fungus provides energy-yielding carbohydrates
to the algae, while the algae helps the fungus absorb essential nutrients. In the light of the above
statements, choose the correct answer:
143.Consider the following statements regarding the mutualistic association called mycorrhizae: I.
Mycorrhizae are associations between fungi and the roots of higher plants.
II. The fungi help the plant in
the absorption of essential nutrients from the soil.
III. The plant provides the fungi with energy-yielding
carbohydrates in return.
IV. Mycorrhizae represent a highly detrimental relationship where the fungus
destroys the root vascular system. Which of the statements given above are correct according to the
NCERT textbook?
Mycorrhizae are associations between fungi and the roots of higher plants.
II. The fungi help the plant in
the absorption of essential nutrients from the soil.
III. The plant provides the fungi with energy-yielding
carbohydrates in return.
IV. Mycorrhizae represent a highly detrimental relationship where the fungus
destroys the root vascular system. Which of the statements given above are correct according to the
NCERT textbook?
144.Given below are two statements, one is labelled as Assertion (A) and the other is labelled as Reason
(R): Assertion (A): Plant-animal mutualistic relationships often involve the payment of 'fees' or rewards
by the plant.
Reason (R): Plants offer rewards in the form of pollen and nectar for pollinators, and juicy
and nutritious fruits for seed dispersers.
In the light of the above statements, choose the correct answer:
(R): Assertion (A): Plant-animal mutualistic relationships often involve the payment of 'fees' or rewards
by the plant.
Reason (R): Plants offer rewards in the form of pollen and nectar for pollinators, and juicy
and nutritious fruits for seed dispersers.
In the light of the above statements, choose the correct answer:
145.Consider the following statements regarding the safeguarding of plant-animal mutualisms against
'cheaters': I. The mutually beneficial system should be safeguarded against 'cheaters'.
II. An example of a
cheater is an animal that tries to steal nectar without aiding in pollination.
III. Plant-animal interactions
often involve the co-evolution of the mutualists.
IV. The evolutions of the flower and its pollinator species
are completely independent of each other to avoid genomic hybridization. Which of the statements given
above are correct according to the NCERT textbook?
'cheaters': I. The mutually beneficial system should be safeguarded against 'cheaters'.
II. An example of a
cheater is an animal that tries to steal nectar without aiding in pollination.
III. Plant-animal interactions
often involve the co-evolution of the mutualists.
IV. The evolutions of the flower and its pollinator species
are completely independent of each other to avoid genomic hybridization. Which of the statements given
above are correct according to the NCERT textbook?
146.Given below are two statements, one is labelled as Assertion (A) and the other is labelled as Reason
(R): Assertion (A): In many species of fig trees, there is a tight one-to-one relationship with the pollinator
species of wasp.
Reason (R): A given fig species can be pollinated only by its partner wasp species and no
other species.
In the light of the above statements, choose the correct answer:
(R): Assertion (A): In many species of fig trees, there is a tight one-to-one relationship with the pollinator
species of wasp.
Reason (R): A given fig species can be pollinated only by its partner wasp species and no
other species.
In the light of the above statements, choose the correct answer:
147.Consider the following statements regarding the mutual rewards exchanged between the fig tree
and its partner wasp: I. The female wasp uses the fig fruit as an oviposition (egg-laying) site.
II. The wasp
larvae nourish themselves by feeding on the developing seeds within the fig fruit.
III. The wasp pollinates
the fig inflorescence while searching for suitable egg-laying sites.
IV. The fig offers the wasp some of its
developing seeds as food in return for the favor of pollination. Which of the statements given above are
correct according to the NCERT textbook?
and its partner wasp: I. The female wasp uses the fig fruit as an oviposition (egg-laying) site.
II. The wasp
larvae nourish themselves by feeding on the developing seeds within the fig fruit.
III. The wasp pollinates
the fig inflorescence while searching for suitable egg-laying sites.
IV. The fig offers the wasp some of its
developing seeds as food in return for the favor of pollination. Which of the statements given above are
correct according to the NCERT textbook?
148.Given below are two statements, one is labelled as Assertion (A) and the other is labelled as Reason
(R): Assertion (A): The female wasp pollinates the fig inflorescence in return for using the developing
seeds to nourish its larvae.
Reason (R): The fig tree offers its mature pollen grains as the primary food
source to sustain the adult flying wasp.
In the light of the above statements, choose the correct answer:
(R): Assertion (A): The female wasp pollinates the fig inflorescence in return for using the developing
seeds to nourish its larvae.
Reason (R): The fig tree offers its mature pollen grains as the primary food
source to sustain the adult flying wasp.
In the light of the above statements, choose the correct answer:
149.Consider the following statements regarding the pollination strategies and diversity of orchids: I.
Orchids show a bewildering diversity of floral patterns.
II. Many orchid patterns have evolved to attract
the right pollinator insect (bees and bumblebees).
III. Orchid floral patterns ensure guaranteed
pollination by the attracted insects.
IV. All orchids offer massive edible rewards in the form of sugary
nectar to their pollinators. Which of the statements given above are correct according to the NCERT
textbook?
Orchids show a bewildering diversity of floral patterns.
II. Many orchid patterns have evolved to attract
the right pollinator insect (bees and bumblebees).
III. Orchid floral patterns ensure guaranteed
pollination by the attracted insects.
IV. All orchids offer massive edible rewards in the form of sugary
nectar to their pollinators. Which of the statements given above are correct according to the NCERT
textbook?
150.Given below are two statements, one is labelled as Assertion (A) and the other is labelled as Reason
(R): Assertion (A): The Mediterranean orchid Ophrys employs 'sexual deceit' to get its flowers pollinated
by a species of bee.
Reason (R): One petal of the Ophrys flower bears an uncanny resemblance to the
female of the bee in size, colour, and markings. In the light of the above statements, choose the correct
answer:
(R): Assertion (A): The Mediterranean orchid Ophrys employs 'sexual deceit' to get its flowers pollinated
by a species of bee.
Reason (R): One petal of the Ophrys flower bears an uncanny resemblance to the
female of the bee in size, colour, and markings. In the light of the above statements, choose the correct
answer:
151.Consider the following statements regarding the physical steps of pollination in the Mediterranean
orchid Ophrys: I. The male bee is attracted to what it perceives as a female bee on the Ophrys flower.
II.
The male bee 'pseudocopulates' with the orchid flower.
III. During the pseudocopulation process, the bee
is dusted with pollen from the flower.
IV. The bee is dusted with pollen by feeding on the nectar reservoirs
of the flower. Which of the statements given above are correct according to the NCERT textbook?
orchid Ophrys: I. The male bee is attracted to what it perceives as a female bee on the Ophrys flower.
II.
The male bee 'pseudocopulates' with the orchid flower.
III. During the pseudocopulation process, the bee
is dusted with pollen from the flower.
IV. The bee is dusted with pollen by feeding on the nectar reservoirs
of the flower. Which of the statements given above are correct according to the NCERT textbook?
152.Given below are two statements, one is labelled as Assertion (A) and the other is labelled as Reason
(R): Assertion (A): When the pollen-dusted male bee pseudocopulates with another Ophrys flower, it
transfers pollen to it and pollinates it.
Reason (R): The male bee has a highly developed cognitive memory
that allows it to recognize individual orchid species and deliberately transfer genetic material to them. In
the light of the above statements, choose the correct answer:
(R): Assertion (A): When the pollen-dusted male bee pseudocopulates with another Ophrys flower, it
transfers pollen to it and pollinates it.
Reason (R): The male bee has a highly developed cognitive memory
that allows it to recognize individual orchid species and deliberately transfer genetic material to them. In
the light of the above statements, choose the correct answer:
153.Consider the following statements regarding the operation of co-evolution in the Ophrys-bee
mutualism: I. If the female bee's color patterns change even slightly during evolution, pollination success
will be reduced.
II. To maintain pollination success, the orchid flower must co-evolve to maintain the
resemblance of its petal to the female bee.
III. Co-evolution ensures that the orchid flower's genome
becomes identical to the bee's genome over geological time.
IV. Co-evolution occurs because the bee's
larval development depends strictly on the vascular cambium of the orchid root. Which of the statements
given above are correct according to the NCERT textbook?
mutualism: I. If the female bee's color patterns change even slightly during evolution, pollination success
will be reduced.
II. To maintain pollination success, the orchid flower must co-evolve to maintain the
resemblance of its petal to the female bee.
III. Co-evolution ensures that the orchid flower's genome
becomes identical to the bee's genome over geological time.
IV. Co-evolution occurs because the bee's
larval development depends strictly on the vascular cambium of the orchid root. Which of the statements
given above are correct according to the NCERT textbook?
154.Given below are two statements, one is labelled as Assertion (A) and the other is labelled as Reason
(R): Assertion (A): Ecology is the study of the relationships of living organisms with the abiotic and biotic
components of their environment.
Reason (R): The abiotic components are represented strictly by other
competing species, while the biotic components are the physico-chemical factors. In the light of the above
statements, choose the correct answer:
(R): Assertion (A): Ecology is the study of the relationships of living organisms with the abiotic and biotic
components of their environment.
Reason (R): The abiotic components are represented strictly by other
competing species, while the biotic components are the physico-chemical factors. In the light of the above
statements, choose the correct answer:
155.According to the Summary of Chapter 11, Ecology is concerned with four levels of biological
organisation. Which of the following is the correct list of these four levels explicitly written in the
Summary?
I. Organisms II. Populations III. Communities IV. Biomes Choose the correct option:
organisation. Which of the following is the correct list of these four levels explicitly written in the
Summary?
I. Organisms II. Populations III. Communities IV. Biomes Choose the correct option:
156.Given below are two statements, one is labelled as Assertion (A) and the other is labelled as Reason
(R): Assertion (A): Evolutionary changes through natural selection take place at the population level.
Reason (R): Population ecology is an important area of ecology because it links ecology to genetics and
evolution.
In the light of the above statements, choose the correct answer:
(R): Assertion (A): Evolutionary changes through natural selection take place at the population level.
Reason (R): Population ecology is an important area of ecology because it links ecology to genetics and
evolution.
In the light of the above statements, choose the correct answer:
157.According to the Summary, populations possess unique attributes that individual organisms do not.
Which of the following represent these attributes explicitly written in the Summary?
I. Birth rates and
death rates.
II. Sex ratio.
III. Age distribution.
IV. Inherent carrying capacity K. Choose the correct
option:
Which of the following represent these attributes explicitly written in the Summary?
I. Birth rates and
death rates.
II. Sex ratio.
III. Age distribution.
IV. Inherent carrying capacity K. Choose the correct
option:
158.Given below are two statements, one is labelled as Assertion (A) and the other is labelled as Reason
(R): Assertion (A): The proportion of different age groups of males and females in a population is often
presented graphically as an age pyramid.
Reason (R): The shape of the age pyramid indicates whether a
population is stationary, growing, or declining. In the light of the above statements, choose the correct
answer:
(R): Assertion (A): The proportion of different age groups of males and females in a population is often
presented graphically as an age pyramid.
Reason (R): The shape of the age pyramid indicates whether a
population is stationary, growing, or declining. In the light of the above statements, choose the correct
answer:
159.According to the Summary, the ecological effects of any factors on a population are generally
reflected in its size (population density). In which of the following ways does the Summary explicitly state
this size may be expressed?
I. Numbers II. Biomass III. Per cent cover IV. Intrinsic r value Choose the
correct option:
reflected in its size (population density). In which of the following ways does the Summary explicitly state
this size may be expressed?
I. Numbers II. Biomass III. Per cent cover IV. Intrinsic r value Choose the
correct option:
160.Given below are two statements, one is labelled as Assertion (A) and the other is labelled as Reason
(R): Assertion (A): Populations grow through births and immigration and decline through deaths and
emigration.
Reason (R): Immigration and emigration represent the primary drivers of growth under
normal long-term stable conditions.
In the light of the above statements, choose the correct answer:
(R): Assertion (A): Populations grow through births and immigration and decline through deaths and
emigration.
Reason (R): Immigration and emigration represent the primary drivers of growth under
normal long-term stable conditions.
In the light of the above statements, choose the correct answer:
161.Consider the following statements regarding the two growth models described in the Summary of
Chapter 11: I. When resources are unlimited, the growth is usually exponential.
II. When resources
become progressively limiting, the growth pattern turns logistic.
III. In either growth model, growth is
ultimately limited by the carrying capacity of the environment.
IV. The intrinsic rate of natural increase
(r) is a measure of the inherent potential of a population to grow. Which of the statements given above are
correct according to the NCERT Summary?
Chapter 11: I. When resources are unlimited, the growth is usually exponential.
II. When resources
become progressively limiting, the growth pattern turns logistic.
III. In either growth model, growth is
ultimately limited by the carrying capacity of the environment.
IV. The intrinsic rate of natural increase
(r) is a measure of the inherent potential of a population to grow. Which of the statements given above are
correct according to the NCERT Summary?
162.Given below are two statements, one is labelled as Assertion (A) and the other is labelled as Reason
(R): Assertion (A): The intrinsic rate of natural increase (r) serves as a measure of the inherent potential
of a population to grow.
Reason (R): The parameter r represents the total number of offspring produced
by a single female parent during its entire reproductive lifespan. In the light of the above statements,
choose the correct answer:
(R): Assertion (A): The intrinsic rate of natural increase (r) serves as a measure of the inherent potential
of a population to grow.
Reason (R): The parameter r represents the total number of offspring produced
by a single female parent during its entire reproductive lifespan. In the light of the above statements,
choose the correct answer:
163.According to the Summary, depending on the outcome, interspecific interactions are classified into
different categories. Which of the following represent the correct category descriptions explicitly written
in the Summary?
I. Competition: both species suffer.
II. Predation and Parasitism: one benefits and the
other suffers.
III. Commensalism: one benefits and the other is unaffected.
IV. Amensalism: one is
harmed, other unaffected. Choose the correct option:
different categories. Which of the following represent the correct category descriptions explicitly written
in the Summary?
I. Competition: both species suffer.
II. Predation and Parasitism: one benefits and the
other suffers.
III. Commensalism: one benefits and the other is unaffected.
IV. Amensalism: one is
harmed, other unaffected. Choose the correct option:
164.Given below are two statements, one is labelled as Assertion (A) and the other is labelled as Reason
(R): Assertion (A): Predation is an exceptionally important ecological process in natural communities.
Reason (R): Through predation, trophic energy transfer is facilitated, and some predators help in
controlling their prey populations.
In the light of the above statements, choose the correct answer:
(R): Assertion (A): Predation is an exceptionally important ecological process in natural communities.
Reason (R): Through predation, trophic energy transfer is facilitated, and some predators help in
controlling their prey populations.
In the light of the above statements, choose the correct answer:
165.Consider the following statements regarding plant defenses as summarized at the end of the
chapter: I. Plants have evolved diverse morphological and chemical defenses against herbivory.
II.
Herbivory represents a form of predation in a broad ecological context.
III. The most common
morphological defense in plants is the secretion of sticky latex.
IV. The plant defenses are described as
completely ineffective in natural ecosystems. Which of the statements given above are correct according to
the NCERT Summary?
chapter: I. Plants have evolved diverse morphological and chemical defenses against herbivory.
II.
Herbivory represents a form of predation in a broad ecological context.
III. The most common
morphological defense in plants is the secretion of sticky latex.
IV. The plant defenses are described as
completely ineffective in natural ecosystems. Which of the statements given above are correct according to
the NCERT Summary?
166.Given below are two statements, one is labelled as Assertion (A) and the other is labelled as Reason
(R): Assertion (A): Gause's Competitive Exclusion Principle is not a universal law for all competing
species in nature.
Reason (R): Many closely related species facing competition have evolved various
mechanisms which facilitate their co-existence. In the light of the above statements, choose the correct
answer:
(R): Assertion (A): Gause's Competitive Exclusion Principle is not a universal law for all competing
species in nature.
Reason (R): Many closely related species facing competition have evolved various
mechanisms which facilitate their co-existence. In the light of the above statements, choose the correct
answer:
167.Consider the following statements regarding the mutualistic associations summarized at the end of
the chapter: I. Some of the most fascinating cases of mutualism in nature are seen in plant-pollinator
interactions.
II. Fig tree and pollinator wasp exhibit a tight species-specific co-evolution.
III. The orchid
Ophrys employs sexual deceit without offering any physical reward.
IV. The Summary explicitly lists
mycorrhizae as the only valid mutualism in marine channels. Which of the statements given above are
correct according to the NCERT Summary?
the chapter: I. Some of the most fascinating cases of mutualism in nature are seen in plant-pollinator
interactions.
II. Fig tree and pollinator wasp exhibit a tight species-specific co-evolution.
III. The orchid
Ophrys employs sexual deceit without offering any physical reward.
IV. The Summary explicitly lists
mycorrhizae as the only valid mutualism in marine channels. Which of the statements given above are
correct according to the NCERT Summary?
168.Given below are two statements, one is labelled as Assertion (A) and the other is labelled as Reason
(R): Assertion (A): If a population growing exponentially doubles in size in 3 years, the intrinsic rate of
increase (r) is approximately 0.231 per year.
Reason (R): For an exponentially growing population, the
doubling time t is mathematically related to r by the formula: r = ln(2) / t. In the light of the above
statements, choose the correct answer:
(R): Assertion (A): If a population growing exponentially doubles in size in 3 years, the intrinsic rate of
increase (r) is approximately 0.231 per year.
Reason (R): For an exponentially growing population, the
doubling time t is mathematically related to r by the formula: r = ln(2) / t. In the light of the above
statements, choose the correct answer:
169.Consider the following statements regarding the interaction between an orchid growing on the
branch of a mango tree (Exercise Q4): I. This interaction is classified as commensalism.
II. The orchid
benefits (+) by getting physical support and access to light.
III. The mango tree is unaffected (0) and
derives neither apparent benefit nor harm.
IV. The orchid is classified as a hemiparasite that penetrates
the mango's xylem to siphon water. Which of the statements given above are correct according to the
NCERT textbook?
branch of a mango tree (Exercise Q4): I. This interaction is classified as commensalism.
II. The orchid
benefits (+) by getting physical support and access to light.
III. The mango tree is unaffected (0) and
derives neither apparent benefit nor harm.
IV. The orchid is classified as a hemiparasite that penetrates
the mango's xylem to siphon water. Which of the statements given above are correct according to the
NCERT textbook?
170.Given below are two statements, one is labelled as Assertion (A) and the other is labelled as Reason
(R): Assertion (A): The biological control method of managing pest insects is based on the principle of
predation.
Reason (R): Predators naturally regulate prey populations, keeping them below economically
damaging thresholds in agroecosystems.
In the light of the above statements, choose the correct answer:
(R): Assertion (A): The biological control method of managing pest insects is based on the principle of
predation.
Reason (R): Predators naturally regulate prey populations, keeping them below economically
damaging thresholds in agroecosystems.
In the light of the above statements, choose the correct answer:
171.Consider the following statements regarding 'camouflage' as a defense mechanism (Exercise Q7c):
I. Camouflage involves cryptic coloration to avoid being detected easily by predators.
II. Examples of
camouflaged species in the text are some species of insects and frogs.
III. Camouflage is described as a
behavioral mutualism where the prey mimics the warning calls of the predator.
IV. Camouflage is a
morphological plant defense designed to attract grazing herbivores. Which of the statements given above
are correct according to the NCERT textbook?
I. Camouflage involves cryptic coloration to avoid being detected easily by predators.
II. Examples of
camouflaged species in the text are some species of insects and frogs.
III. Camouflage is described as a
behavioral mutualism where the prey mimics the warning calls of the predator.
IV. Camouflage is a
morphological plant defense designed to attract grazing herbivores. Which of the statements given above
are correct according to the NCERT textbook?
172.Given below are two statements, one is labelled as Assertion (A) and the other is labelled as Reason
(R): Assertion (A): Interspecific competition is a process where the fitness of one species is significantly
lower in the presence of another species.
Reason (R): It occurs strictly between taxonomically identical
chromosome variants competing for unlimited cosmic energy. In the light of the above statements, choose
the correct answer:
(R): Assertion (A): Interspecific competition is a process where the fitness of one species is significantly
lower in the presence of another species.
Reason (R): It occurs strictly between taxonomically identical
chromosome variants competing for unlimited cosmic energy. In the light of the above statements, choose
the correct answer:
173.According to Exercise Q9 of the textbook, which of the following statements represents the option
that explains parasitism best?
I. One organism is benefited, other is affected.
II. One organism is
benefited, other is not affected.
III. Both the organisms are benefited.
IV. One organism is benefited, other
is harmed (detrimentally affected). Choose the correct option representing the best textbook choice:
that explains parasitism best?
I. One organism is benefited, other is affected.
II. One organism is
benefited, other is not affected.
III. Both the organisms are benefited.
IV. One organism is benefited, other
is harmed (detrimentally affected). Choose the correct option representing the best textbook choice:
174.Given below are two statements, one is labelled as Assertion (A) and the other is labelled as Reason
(R): Assertion (A): Birth rates and death rates represent important characteristics of a population.
Reason
(R): These rates refer to per capita births and deaths calculated with respect to members of the
population.
In the light of the above statements, choose the correct answer:
(R): Assertion (A): Birth rates and death rates represent important characteristics of a population.
Reason
(R): These rates refer to per capita births and deaths calculated with respect to members of the
population.
In the light of the above statements, choose the correct answer:
175.Consider the following statements regarding the population concepts covered in Section 11.1: I. In
nature, we rarely find isolated, single individuals of any species.
II. Majority of them live in groups in a
well-defined geographical area.
III. They potentially interbreed and thus constitute a population.
IV. The
cormorants in a wetland and teakwood trees in a forest tract represent examples of populations. Which of
the statements given above are correct according to the NCERT textbook?
nature, we rarely find isolated, single individuals of any species.
II. Majority of them live in groups in a
well-defined geographical area.
III. They potentially interbreed and thus constitute a population.
IV. The
cormorants in a wetland and teakwood trees in a forest tract represent examples of populations. Which of
the statements given above are correct according to the NCERT textbook?
176.Given below are two statements, one is labelled as Assertion (A) and the other is labelled as Reason
(R): Assertion (A): If in a pond there were 20 lotus plants last year and 8 new plants are added, the birth
rate is exactly 0.4 offspring per lotus per year.
Reason (R): If 4 fruitflies in a laboratory population of 40
died during a week, the death rate is exactly 0.1 individuals per fruitfly per week. In the light of the above
statements, choose the correct answer:
(R): Assertion (A): If in a pond there were 20 lotus plants last year and 8 new plants are added, the birth
rate is exactly 0.4 offspring per lotus per year.
Reason (R): If 4 fruitflies in a laboratory population of 40
died during a week, the death rate is exactly 0.1 individuals per fruitfly per week. In the light of the above
statements, choose the correct answer:
177.Consider the following statements regarding the age pyramids for the human population shown in
Figure 11.1: I. The shape of the pyramids reflects the growth status of the population.
II. The three growth
statuses represented are growing, stable, and declining.
III. The stable pyramid has nearly equal pre-
reproductive and reproductive cohorts.
IV. The declining pyramid has a highly expanded pre-
reproductive base. Which of the statements given above are correct according to the NCERT textbook?
Figure 11.1: I. The shape of the pyramids reflects the growth status of the population.
II. The three growth
statuses represented are growing, stable, and declining.
III. The stable pyramid has nearly equal pre-
reproductive and reproductive cohorts.
IV. The declining pyramid has a highly expanded pre-
reproductive base. Which of the statements given above are correct according to the NCERT textbook?
178.Given below are two statements, one is labelled as Assertion (A) and the other is labelled as Reason
(R): Assertion (A): The tiger census in national parks and reserves is often based on pug marks and fecal
pellets.
Reason (R): Pug marks and fecal pellets are direct visual counts that establish absolute population
densities with 100% molecular certainty.
In the light of the above statements, choose the correct answer:
(R): Assertion (A): The tiger census in national parks and reserves is often based on pug marks and fecal
pellets.
Reason (R): Pug marks and fecal pellets are direct visual counts that establish absolute population
densities with 100% molecular certainty.
In the light of the above statements, choose the correct answer:
179.Consider the following statements regarding the four basic processes of population growth: I.
Natality and Immigration contribute to an increase in population density.
II. Mortality and Emigration
contribute to a decrease in population density.
III. Under normal conditions, births and deaths are the
most important factors influencing population density.
IV. In a newly colonised habitat, immigration may
contribute more significantly to population growth than birth rates. Which of the statements given above
are correct according to the NCERT textbook?
Natality and Immigration contribute to an increase in population density.
II. Mortality and Emigration
contribute to a decrease in population density.
III. Under normal conditions, births and deaths are the
most important factors influencing population density.
IV. In a newly colonised habitat, immigration may
contribute more significantly to population growth than birth rates. Which of the statements given above
are correct according to the NCERT textbook?
180.Given below are two statements, one is labelled as Assertion (A) and the other is labelled as Reason
(R): Assertion (A): A population growing in a habitat with limited resources results in a sigmoid (S-
shaped) curve.
Reason (R): This type of growth is called Verhulst-Pearl Logistic Growth and exhibits a
carrying capacity K.
In the light of the above statements, choose the correct answer:
(R): Assertion (A): A population growing in a habitat with limited resources results in a sigmoid (S-
shaped) curve.
Reason (R): This type of growth is called Verhulst-Pearl Logistic Growth and exhibits a
carrying capacity K.
In the light of the above statements, choose the correct answer:
181.Consider the following statements regarding the competition in shallow South American lakes: I.
Visiting flamingoes and resident fishes compete for their common food.
II. The common food resource is
the zooplankton suspended in the lake.
III. The lakes where this competition occurs are located in shallow
regions of North America.
IV. The competing species are closely related taxonomic lineages. Which of the
statements given above are correct according to the NCERT textbook?
Visiting flamingoes and resident fishes compete for their common food.
II. The common food resource is
the zooplankton suspended in the lake.
III. The lakes where this competition occurs are located in shallow
regions of North America.
IV. The competing species are closely related taxonomic lineages. Which of the
statements given above are correct according to the NCERT textbook?
182.Given below are two statements, one is labelled as Assertion (A) and the other is labelled as Reason
(R): Assertion (A): Resources need not be limiting for competition to occur in natural habitats.
Reason
(R): In interference competition, the feeding efficiency of one species is reduced due to the interfering
presence of the other species, even if food and space are abundant. In the light of the above statements,
choose the correct answer:
(R): Assertion (A): Resources need not be limiting for competition to occur in natural habitats.
Reason
(R): In interference competition, the feeding efficiency of one species is reduced due to the interfering
presence of the other species, even if food and space are abundant. In the light of the above statements,
choose the correct answer:
183.Consider the following statements regarding the best ecological definition of competition: I.
Competition is best defined as a process where the fitness of one species is significantly lower in the
presence of another.
II. The biological fitness in competition is measured in terms of 'r', the intrinsic rate
of increase.
III. In the presence of a superior competitor, the inferior competitor's r value increases
dramatically.
IV. In all competitive scenarios, both species always experience a mutual increase in their
carrying capacity K. Which of the statements given above are correct according to the NCERT textbook?
Competition is best defined as a process where the fitness of one species is significantly lower in the
presence of another.
II. The biological fitness in competition is measured in terms of 'r', the intrinsic rate
of increase.
III. In the presence of a superior competitor, the inferior competitor's r value increases
dramatically.
IV. In all competitive scenarios, both species always experience a mutual increase in their
carrying capacity K. Which of the statements given above are correct according to the NCERT textbook?
184.Given below are two statements, one is labelled as Assertion (A) and the other is labelled as Reason
(R): Assertion (A): The Abingdon tortoise in the Galapagos Islands became extinct within a decade after
goats were introduced.
Reason (R): The extinction occurred apparently due to the greater browsing
efficiency of the goats.
In the light of the above statements, choose the correct answer:
(R): Assertion (A): The Abingdon tortoise in the Galapagos Islands became extinct within a decade after
goats were introduced.
Reason (R): The extinction occurred apparently due to the greater browsing
efficiency of the goats.
In the light of the above statements, choose the correct answer:
185.Consider the following statements regarding the phenomenon of 'competitive release' described in
Chapter 11: I. A species restricted to a small geographical area expands its range dramatically when the
competing species is experimentally removed.
II. Competitive release serves as strong evidence for the
occurrence of competition in nature.
III. The range expansion is driven by the immediate synthesis of
developmental hormones in the host seedling.
IV. Competitive release occurs only when both competing
species undergo mutual extinction. Which of the statements given above are correct according to the
NCERT textbook?
Chapter 11: I. A species restricted to a small geographical area expands its range dramatically when the
competing species is experimentally removed.
II. Competitive release serves as strong evidence for the
occurrence of competition in nature.
III. The range expansion is driven by the immediate synthesis of
developmental hormones in the host seedling.
IV. Competitive release occurs only when both competing
species undergo mutual extinction. Which of the statements given above are correct according to the
NCERT textbook?
186.Given below are two statements, one is labelled as Assertion (A) and the other is labelled as Reason
(R): Assertion (A): On the rocky sea coasts of Scotland, the larger barnacle Balanus dominates the
intertidal area and excludes Chathamalus.
Reason (R): Connell's elegant field experiments showed that
Balanus is the competitively superior barnacle in this intertidal zone. In the light of the above statements,
choose the correct answer:
(R): Assertion (A): On the rocky sea coasts of Scotland, the larger barnacle Balanus dominates the
intertidal area and excludes Chathamalus.
Reason (R): Connell's elegant field experiments showed that
Balanus is the competitively superior barnacle in this intertidal zone. In the light of the above statements,
choose the correct answer:
187.Consider the following statements regarding the sensitivity of different taxonomic groups to
competition: I. In general, herbivores and plants appear to be more adversely affected by competition
than carnivores.
II. Carnivores are highly sensitive to exclusion because they have complex territorial
home ranges.
III. Plants appear to be completely immune to competitive exclusion in natural forests.
IV.
In general, carnivores are more adversely affected by competition than plants and herbivores. Which of
the statements given above is/are correct according to the NCERT textbook?
competition: I. In general, herbivores and plants appear to be more adversely affected by competition
than carnivores.
II. Carnivores are highly sensitive to exclusion because they have complex territorial
home ranges.
III. Plants appear to be completely immune to competitive exclusion in natural forests.
IV.
In general, carnivores are more adversely affected by competition than plants and herbivores. Which of
the statements given above is/are correct according to the NCERT textbook?
188.Given below are two statements, one is labelled as Assertion (A) and the other is labelled as Reason
(R): Assertion (A): Gause's Competitive Exclusion Principle is not accepted as a universal law of nature
by modern ecologists.
Reason (R): Species facing competition might evolve mechanisms that promote co-
existence rather than exclusion, such as resource partitioning. In the light of the above statements, choose
the correct answer:
(R): Assertion (A): Gause's Competitive Exclusion Principle is not accepted as a universal law of nature
by modern ecologists.
Reason (R): Species facing competition might evolve mechanisms that promote co-
existence rather than exclusion, such as resource partitioning. In the light of the above statements, choose
the correct answer:
189.Consider the following statements regarding the resource partitioning study conducted by
MacArthur on warblers: I. He showed that five closely related species of warblers living on the same tree
were able to avoid competition.
II. The warblers avoided competition and co-existed due to behavioral
differences in their foraging activities.
III. The study was conducted on five totally unrelated species of
migratory eagles.
IV. The warblers co-existed by dividing the tree roots into distinct developmental
compartments. Which of the statements given above are correct according to the NCERT textbook?
MacArthur on warblers: I. He showed that five closely related species of warblers living on the same tree
were able to avoid competition.
II. The warblers avoided competition and co-existed due to behavioral
differences in their foraging activities.
III. The study was conducted on five totally unrelated species of
migratory eagles.
IV. The warblers co-existed by dividing the tree roots into distinct developmental
compartments. Which of the statements given above are correct according to the NCERT textbook?
190.Given below are two statements, one is labelled as Assertion (A) and the other is labelled as Reason
(R): Assertion (A): The human liver fluke is a trematode parasite that depends on two intermediate hosts
to complete its life cycle.
Reason (R): The two intermediate hosts required by the liver fluke are a snail
and a fish.
In the light of the above statements, choose the correct answer:
(R): Assertion (A): The human liver fluke is a trematode parasite that depends on two intermediate hosts
to complete its life cycle.
Reason (R): The two intermediate hosts required by the liver fluke are a snail
and a fish.
In the light of the above statements, choose the correct answer:
191.Consider the following statements regarding the biological impacts of parasites on their hosts: I. A
majority of parasites harm the host, reducing host survival, growth, and reproduction.
II. Parasites reduce
the population density of the host species.
III. Parasites render the host more vulnerable to predation by
making it physically weak.
IV. Highly adapted parasites always increase the host's evolutionary fitness to
promote mutual survival. Which of the statements given above are correct according to the NCERT
textbook?
majority of parasites harm the host, reducing host survival, growth, and reproduction.
II. Parasites reduce
the population density of the host species.
III. Parasites render the host more vulnerable to predation by
making it physically weak.
IV. Highly adapted parasites always increase the host's evolutionary fitness to
promote mutual survival. Which of the statements given above are correct according to the NCERT
textbook?
192.Given below are two statements, one is labelled as Assertion (A) and the other is labelled as Reason
(R): Assertion (A): Lice on humans and ticks on dogs represent familiar examples of ectoparasites.
Reason
(R): Ectoparasites feed on the external surface of the host organism. In the light of the above statements,
choose the correct answer:
(R): Assertion (A): Lice on humans and ticks on dogs represent familiar examples of ectoparasites.
Reason
(R): Ectoparasites feed on the external surface of the host organism. In the light of the above statements,
choose the correct answer:
193.Consider the following statements regarding ectoparasitic adaptations in plants and marine
systems: I. Cuscuta is a parasitic plant commonly found growing on hedge plants.
II. Cuscuta has
completely lost its chlorophyll and leaves in the course of evolution.
III. Many marine fish are infested
with ectoparasitic copepods.
IV. Copepods are described in the text as highly adapted marine vascular
plants. Which of the statements given above are correct according to the NCERT textbook?
systems: I. Cuscuta is a parasitic plant commonly found growing on hedge plants.
II. Cuscuta has
completely lost its chlorophyll and leaves in the course of evolution.
III. Many marine fish are infested
with ectoparasitic copepods.
IV. Copepods are described in the text as highly adapted marine vascular
plants. Which of the statements given above are correct according to the NCERT textbook?
194.Given below are two statements, one is labelled as Assertion (A) and the other is labelled as Reason
(R): Assertion (A): The female mosquito is not considered a parasite, although it needs our blood for
reproduction.
Reason (R): The female mosquito is a vector that transfers the malarial parasite to its
primary human host.
In the light of the above statements, choose the correct answer:
(R): Assertion (A): The female mosquito is not considered a parasite, although it needs our blood for
reproduction.
Reason (R): The female mosquito is a vector that transfers the malarial parasite to its
primary human host.
In the light of the above statements, choose the correct answer:
195.Consider the following statements regarding the anatomical and reproductive traits of
endoparasites: I. Endoparasites live inside the host body at different sites (liver, kidney, lungs, red blood
cells).
II. Their morphological and anatomical features are greatly simplified.
III. Their reproductive
potential is highly emphasized.
IV. Their digestive systems are highly complex to process diverse host
foods. Which of the statements given above are correct according to the NCERT textbook?
endoparasites: I. Endoparasites live inside the host body at different sites (liver, kidney, lungs, red blood
cells).
II. Their morphological and anatomical features are greatly simplified.
III. Their reproductive
potential is highly emphasized.
IV. Their digestive systems are highly complex to process diverse host
foods. Which of the statements given above are correct according to the NCERT textbook?
196.Given below are two statements, one is labelled as Assertion (A) and the other is labelled as Reason
(R): Assertion (A): The life cycles of endoparasites are generally more complex than those of ectoparasites.
Reason (R): The complexity of endoparasitic life cycles is driven by their extreme specialisation to live
inside the host body.
In the light of the above statements, choose the correct answer:
(R): Assertion (A): The life cycles of endoparasites are generally more complex than those of ectoparasites.
Reason (R): The complexity of endoparasitic life cycles is driven by their extreme specialisation to live
inside the host body.
In the light of the above statements, choose the correct answer:
197.Consider the following statements regarding brood parasitism in birds: I. The parasitic bird lays its
eggs in the nest of its host and lets the host incubate them.
II. During evolution, the eggs of the parasitic
bird have evolved to resemble the host's egg in size and color.
III. The resemblance reduces the chances of
the host bird detecting the foreign eggs and ejecting them.
IV. The host eggs always shrink in size to
accommodate the parasitic egg in the nest. Which of the statements given above are correct according to
the NCERT textbook?
eggs in the nest of its host and lets the host incubate them.
II. During evolution, the eggs of the parasitic
bird have evolved to resemble the host's egg in size and color.
III. The resemblance reduces the chances of
the host bird detecting the foreign eggs and ejecting them.
IV. The host eggs always shrink in size to
accommodate the parasitic egg in the nest. Which of the statements given above are correct according to
the NCERT textbook?
198.Given below are two statements, one is labelled as Assertion (A) and the other is labelled as Reason
(R): Assertion (A): In India, brood parasitism is classically observed in action between the cuckoo (koel)
and the crow.
Reason (R): The breeding season for these birds, where this interaction occurs, is strictly
during the winter to spring months.
In the light of the above statements, choose the correct answer:
(R): Assertion (A): In India, brood parasitism is classically observed in action between the cuckoo (koel)
and the crow.
Reason (R): The breeding season for these birds, where this interaction occurs, is strictly
during the winter to spring months.
In the light of the above statements, choose the correct answer:
199.Consider the following statements regarding the species pairings and neutral hosts in
commensalism: I. An orchid grows as an epiphyte on a mango branch.
II. Barnacles grow on the back of a
whale.
III. The orchid and barnacles benefit, while the mango tree and the whale are unaffected.
IV. The
orchid is classified as a vascular parasite that drains sap from the mango branch. Which of the statements
given above are correct according to the NCERT textbook?
commensalism: I. An orchid grows as an epiphyte on a mango branch.
II. Barnacles grow on the back of a
whale.
III. The orchid and barnacles benefit, while the mango tree and the whale are unaffected.
IV. The
orchid is classified as a vascular parasite that drains sap from the mango branch. Which of the statements
given above are correct according to the NCERT textbook?
200.Given below are two statements, one is labelled as Assertion (A) and the other is labelled as Reason
(R): Assertion (A): The cattle egret and grazing cattle in close association represents a classic example of
commensalism.
Reason (R): The grazing cattle stir up and flush out insects from the vegetation as they
move, making it easier for egrets to catch food. In the light of the above statements, choose the correct
answer:
(R): Assertion (A): The cattle egret and grazing cattle in close association represents a classic example of
commensalism.
Reason (R): The grazing cattle stir up and flush out insects from the vegetation as they
move, making it easier for egrets to catch food. In the light of the above statements, choose the correct
answer:
201.Consider the following statements regarding the commensal interaction between the clown fish and
the sea anemone: I. The clown fish lives among the stinging tentacles of the sea anemone.
II. The clown
fish gets protection from predators, which stay away from the stinging tentacles.
III. The sea anemone
derives a major nutritional benefit by digesting the fecal pellets of the clown fish.
IV. The sea anemone
does not appear to derive any benefit from hosting the clown fish. Which of the statements given above are
correct according to the NCERT textbook?
the sea anemone: I. The clown fish lives among the stinging tentacles of the sea anemone.
II. The clown
fish gets protection from predators, which stay away from the stinging tentacles.
III. The sea anemone
derives a major nutritional benefit by digesting the fecal pellets of the clown fish.
IV. The sea anemone
does not appear to derive any benefit from hosting the clown fish. Which of the statements given above are
correct according to the NCERT textbook?
202.Given below are two statements, one is labelled as Assertion (A) and the other is labelled as Reason
(R): Assertion (A): Lichens represent an intimate mutualistic relationship between a fungus and
photosynthesising algae or cyanobacteria.
Reason (R): In Table 11.1, the outcome matrix for mutualistic
relationships is designated as a (+ , +) interaction. In the light of the above statements, choose the correct
answer:
(R): Assertion (A): Lichens represent an intimate mutualistic relationship between a fungus and
photosynthesising algae or cyanobacteria.
Reason (R): In Table 11.1, the outcome matrix for mutualistic
relationships is designated as a (+ , +) interaction. In the light of the above statements, choose the correct
answer:
203.Consider the following statements regarding the mutualistic mycorrhizal associations: I.
Mycorrhizae are associations between fungi and the roots of higher plants.
II. The fungi help the plant in
the absorption of essential nutrients from the soil.
III. The plant provides the fungi with energy-yielding
carbohydrates.
IV. The plant provides the fungi with atmospheric nitrogen fixed inside root nodules.
Which of the statements given above are correct according to the NCERT textbook?
Mycorrhizae are associations between fungi and the roots of higher plants.
II. The fungi help the plant in
the absorption of essential nutrients from the soil.
III. The plant provides the fungi with energy-yielding
carbohydrates.
IV. The plant provides the fungi with atmospheric nitrogen fixed inside root nodules.
Which of the statements given above are correct according to the NCERT textbook?
204.Given below are two statements, one is labelled as Assertion (A) and the other is labelled as Reason
(R): Assertion (A): Plants offer rewards in the form of nectar, pollen, or juicy fruits to animal pollinators
and dispersers.
Reason (R): These physical rewards are ecologically necessary to prevent the animal from
cheating by consuming resources without performing pollination. In the light of the above statements,
choose the correct answer:
(R): Assertion (A): Plants offer rewards in the form of nectar, pollen, or juicy fruits to animal pollinators
and dispersers.
Reason (R): These physical rewards are ecologically necessary to prevent the animal from
cheating by consuming resources without performing pollination. In the light of the above statements,
choose the correct answer:
205.Consider the following statements regarding the co-evolution of plant-pollinator interactions and
the threat of 'cheaters': I. Mutualisms are vulnerable to cheaters, which try to search out rewards without
performing services.
II. Plant-pollinator interactions often exhibit tight co-evolution of the flower and its
pollinator species.
III. The evolution of the flower and its pollinator partner are tightly linked with one
another.
IV. Co-evolution completely eliminates the possibility of any nectar robbers arising in nature.
Which of the statements given above are correct according to the NCERT textbook?
the threat of 'cheaters': I. Mutualisms are vulnerable to cheaters, which try to search out rewards without
performing services.
II. Plant-pollinator interactions often exhibit tight co-evolution of the flower and its
pollinator species.
III. The evolution of the flower and its pollinator partner are tightly linked with one
another.
IV. Co-evolution completely eliminates the possibility of any nectar robbers arising in nature.
Which of the statements given above are correct according to the NCERT textbook?
206.Given below are two statements, one is labelled as Assertion (A) and the other is labelled as Reason
(R): Assertion (A): A given fig species can be pollinated only by its partner wasp species and no other wasp
species.
Reason (R): This absolute specificity ensures that only the co-evolved wasp partner receives host
seed rewards for its larvae.
In the light of the above statements, choose the correct answer:
(R): Assertion (A): A given fig species can be pollinated only by its partner wasp species and no other wasp
species.
Reason (R): This absolute specificity ensures that only the co-evolved wasp partner receives host
seed rewards for its larvae.
In the light of the above statements, choose the correct answer:
207.Consider the following statements regarding the physical steps of the fig-wasp mutualistic
interaction: I. The female wasp uses the fig fruit not only as an oviposition (egg-laying) site but uses the
developing seeds within the fruit for nourishing its larvae.
II. The wasp pollinates the fig inflorescence
while searching for suitable egg-laying sites.
III. The fig species offers the wasp some of its developing
seeds as food for the developing wasp larvae.
IV. The wasp larvae feed exclusively on the toxic latex
secreted by the fig fruit skin. Which of the statements given above are correct according to the NCERT
textbook?
interaction: I. The female wasp uses the fig fruit not only as an oviposition (egg-laying) site but uses the
developing seeds within the fruit for nourishing its larvae.
II. The wasp pollinates the fig inflorescence
while searching for suitable egg-laying sites.
III. The fig species offers the wasp some of its developing
seeds as food for the developing wasp larvae.
IV. The wasp larvae feed exclusively on the toxic latex
secreted by the fig fruit skin. Which of the statements given above are correct according to the NCERT
textbook?
208.Given below are two statements, one is labelled as Assertion (A) and the other is labelled as Reason
(R): Assertion (A): The Mediterranean orchid Ophrys employs a highly unique strategy called 'sexual
deceit' to achieve pollination.
Reason (R): Ophrys does not offer any food rewards (like nectar or pollen)
to its pollinator bee species.
In the light of the above statements, choose the correct answer:
(R): Assertion (A): The Mediterranean orchid Ophrys employs a highly unique strategy called 'sexual
deceit' to achieve pollination.
Reason (R): Ophrys does not offer any food rewards (like nectar or pollen)
to its pollinator bee species.
In the light of the above statements, choose the correct answer:
209.Consider the following statements regarding the physical mimicry employed by the Mediterranean
orchid Ophrys: I. One petal of the Ophrys flower bears an uncanny resemblance to the female of the bee
species.
II. The resemblance to the female bee includes size, color, and markings.
III. The male bee is
attracted to this petal, which it perceives as a female bee.
IV. The entire orchid plant undergoes rapid cell
division to physically envelope the male bee during pollination. Which of the statements given above are
correct according to the NCERT textbook?
orchid Ophrys: I. One petal of the Ophrys flower bears an uncanny resemblance to the female of the bee
species.
II. The resemblance to the female bee includes size, color, and markings.
III. The male bee is
attracted to this petal, which it perceives as a female bee.
IV. The entire orchid plant undergoes rapid cell
division to physically envelope the male bee during pollination. Which of the statements given above are
correct according to the NCERT textbook?
210.Given below are two statements, one is labelled as Assertion (A) and the other is labelled as Reason
(R): Assertion (A): During the process of pseudocopulation with the Ophrys flower, the male bee is dusted
with pollen.
Reason (R): The Ophrys flower petal bears an uncanny resemblance to the female bee in size,
color, and markings.
In the light of the above statements, choose the correct answer:
(R): Assertion (A): During the process of pseudocopulation with the Ophrys flower, the male bee is dusted
with pollen.
Reason (R): The Ophrys flower petal bears an uncanny resemblance to the female bee in size,
color, and markings.
In the light of the above statements, choose the correct answer:
211.Consider the following statements regarding the operation of co-evolution in the Mediterranean
orchid Ophrys-bee mutualism: I. If the female bee's color patterns change even slightly during evolution,
pollination success will be reduced.
II. To maintain pollination success, the orchid flower must co-evolve to
maintain the resemblance of its petal to the female bee.
III. The evolutionary change in the female bee's
color pattern is driven by the immediate accumulation of heavy isotopes in the host foliage.
IV. If the
female bee's color patterns change, the orchid flower automatically mutates its entire root system into a
mycorrhizal node. Which of the statements given above are correct according to the NCERT textbook?
orchid Ophrys-bee mutualism: I. If the female bee's color patterns change even slightly during evolution,
pollination success will be reduced.
II. To maintain pollination success, the orchid flower must co-evolve to
maintain the resemblance of its petal to the female bee.
III. The evolutionary change in the female bee's
color pattern is driven by the immediate accumulation of heavy isotopes in the host foliage.
IV. If the
female bee's color patterns change, the orchid flower automatically mutates its entire root system into a
mycorrhizal node. Which of the statements given above are correct according to the NCERT textbook?
212.Given below are two statements, one is labelled as Assertion (A) and the other is labelled as Reason
(R): Assertion (A): When the pollen-dusted male bee pseudocopulates with another Ophrys flower, it
transfers pollen to it and pollinates it.
Reason (R): The male bee has a highly developed cognitive memory
that allows it to recognize individual orchid species and deliberately transfer genetic material to them. In
the light of the above statements, choose the correct answer:
(R): Assertion (A): When the pollen-dusted male bee pseudocopulates with another Ophrys flower, it
transfers pollen to it and pollinates it.
Reason (R): The male bee has a highly developed cognitive memory
that allows it to recognize individual orchid species and deliberately transfer genetic material to them. In
the light of the above statements, choose the correct answer:
213.Consider the following statements regarding the early life and academic milestones of Ramdeo
Misra: I. He was born on 26 August 1908.
II. He obtained his Ph.D. in Ecology in 1937 from Leeds
University in the UK.
III. His doctoral supervisor was the renowned Prof. W. H. Pearsall, FRS.
IV. The
university from which he received his doctorate was Banaras Hindu University. Which of the statements
given above are correct according to the NCERT Unit X introduction?
Misra: I. He was born on 26 August 1908.
II. He obtained his Ph.D. in Ecology in 1937 from Leeds
University in the UK.
III. His doctoral supervisor was the renowned Prof. W. H. Pearsall, FRS.
IV. The
university from which he received his doctorate was Banaras Hindu University. Which of the statements
given above are correct according to the NCERT Unit X introduction?
214.Given below are two statements, one is labelled as Assertion (A) and the other is labelled as Reason
(R): Assertion (A): Ramdeo Misra established the Department of Botany at the Banaras Hindu University,
Varanasi.
Reason (R): His research laid the foundations for the understanding of tropical communities
and their succession in India.
In the light of the above statements, choose the correct answer:
(R): Assertion (A): Ramdeo Misra established the Department of Botany at the Banaras Hindu University,
Varanasi.
Reason (R): His research laid the foundations for the understanding of tropical communities
and their succession in India.
In the light of the above statements, choose the correct answer:
215.Consider the following statements regarding the administrative achievements and honors of
Ramdeo Misra: I. He was honored with the Fellowships of the Indian National Science Academy and
World Academy of Arts and Science.
II. He received the prestigious Sanjay Gandhi Award in
Environment and Ecology.
III. Due to his efforts, the Government of India established the National
Committee for Environmental Planning and Coordination in 1972.
IV. His efforts directly led to the
immediate establishment of the Ministry of Environment and Forests in 1972. Which of the statements
given above are correct according to the NCERT text?
Ramdeo Misra: I. He was honored with the Fellowships of the Indian National Science Academy and
World Academy of Arts and Science.
II. He received the prestigious Sanjay Gandhi Award in
Environment and Ecology.
III. Due to his efforts, the Government of India established the National
Committee for Environmental Planning and Coordination in 1972.
IV. His efforts directly led to the
immediate establishment of the Ministry of Environment and Forests in 1972. Which of the statements
given above are correct according to the NCERT text?
216.Given below are two statements, one is labelled as Assertion (A) and the other is labelled as Reason
(R): Assertion (A): Ramdeo Misra is widely revered as the Father of Ecology in India.
Reason (R): Under
his direct supervision, over 50 scholars obtained their Ph.D. degrees, and he formulated the first
postgraduate course in ecology in India.
In the light of the above statements, choose the correct answer:
(R): Assertion (A): Ramdeo Misra is widely revered as the Father of Ecology in India.
Reason (R): Under
his direct supervision, over 50 scholars obtained their Ph.D. degrees, and he formulated the first
postgraduate course in ecology in India.
In the light of the above statements, choose the correct answer:
217.Consider the following statements regarding the holistic perspective described in the Unit X
introduction: I. Ecology is basically concerned with four levels of biological organisation.
II. The four
levels are organisms, populations, communities, and biomes.
III. Ecology is a subject which studies the
interactions among organisms and between the organism and its physical (abiotic) environment.
IV. In
ecology, the individual organism is completely ignored to focus strictly on biome productivity. Which of
the statements given above are correct according to the NCERT textbook?
introduction: I. Ecology is basically concerned with four levels of biological organisation.
II. The four
levels are organisms, populations, communities, and biomes.
III. Ecology is a subject which studies the
interactions among organisms and between the organism and its physical (abiotic) environment.
IV. In
ecology, the individual organism is completely ignored to focus strictly on biome productivity. Which of
the statements given above are correct according to the NCERT textbook?
218.Given below are two statements, one is labelled as Assertion (A) and the other is labelled as Reason
(R): Assertion (A): Ecology at the organismic level is essentially physiological ecology.
Reason (R):
Organismic ecology tries to understand how different organisms are adapted to their environments in
terms of not only survival but also reproduction. In the light of the above statements, choose the correct
answer:
(R): Assertion (A): Ecology at the organismic level is essentially physiological ecology.
Reason (R):
Organismic ecology tries to understand how different organisms are adapted to their environments in
terms of not only survival but also reproduction. In the light of the above statements, choose the correct
answer:
219.Consider the following statements regarding the physical factors that lead to the formation of major
biomes on earth: I. Rotation of our planet around the sun and the tilt of its axis cause annual variations in
the intensity and duration of temperature.
II. These temperature variations, combined with annual
variation in precipitation, account for the formation of major biomes.
III. Precipitation includes both rain
and snow.
IV. The rotation and tilt cause absolute constant solar intensity across all latitudes of the globe.
Which of the statements given above are correct according to the NCERT textbook?
biomes on earth: I. Rotation of our planet around the sun and the tilt of its axis cause annual variations in
the intensity and duration of temperature.
II. These temperature variations, combined with annual
variation in precipitation, account for the formation of major biomes.
III. Precipitation includes both rain
and snow.
IV. The rotation and tilt cause absolute constant solar intensity across all latitudes of the globe.
Which of the statements given above are correct according to the NCERT textbook?
220.Given below are two statements, one is labelled as Assertion (A) and the other is labelled as Reason
(R): Assertion (A): Desert, rain forest, deciduous forest, and sea coast represent the major biomes of India.
Reason (R): These biomes are formed strictly within the geographical borders of India due to the heavy
monsoonal rain patterns.
In the light of the above statements, choose the correct answer:
(R): Assertion (A): Desert, rain forest, deciduous forest, and sea coast represent the major biomes of India.
Reason (R): These biomes are formed strictly within the geographical borders of India due to the heavy
monsoonal rain patterns.
In the light of the above statements, choose the correct answer:
221.Consider the following statements regarding the physical and biological boundaries of a species'
ecological niche: I. Within each biome, regional and local variations lead to the formation of a wide
variety of habitats.
II. Each organism has an invariably defined range of conditions that it can tolerate.
III. The distinct role of an organism in the ecological system, along with its tolerated conditions and
resources, forms its niche.
IV. The niche of a species is completely identical to its geographical habitat,
with no functional distinction. Which of the statements given above are correct according to the NCERT
textbook?
ecological niche: I. Within each biome, regional and local variations lead to the formation of a wide
variety of habitats.
II. Each organism has an invariably defined range of conditions that it can tolerate.
III. The distinct role of an organism in the ecological system, along with its tolerated conditions and
resources, forms its niche.
IV. The niche of a species is completely identical to its geographical habitat,
with no functional distinction. Which of the statements given above are correct according to the NCERT
textbook?
222.Given below are two statements, one is labelled as Assertion (A) and the other is labelled as Reason
(R): Assertion (A): The physical-chemical (abiotic) structural features of a habitat alone do not completely
define it.
Reason (R): A habitat includes biotic components such as pathogens, parasites, predators, and
competitors with which the organism interacts constantly. In the light of the above statements, choose the
correct answer:
(R): Assertion (A): The physical-chemical (abiotic) structural features of a habitat alone do not completely
define it.
Reason (R): A habitat includes biotic components such as pathogens, parasites, predators, and
competitors with which the organism interacts constantly. In the light of the above statements, choose the
correct answer:
223.Consider the following statements regarding the global and regional temperature gradients on
earth: I. Temperature is the most ecologically relevant environmental factor.
II. It decreases progressively
from the equator towards the poles and from plains to the mountain tops.
III. It ranges from subzero
levels in polar areas to >50°C in tropical deserts in summer.
IV. In deep hydrothermal vents and hot
springs, average temperatures exceed 100°C. Which of the statements given above are correct according
to the NCERT textbook?
earth: I. Temperature is the most ecologically relevant environmental factor.
II. It decreases progressively
from the equator towards the poles and from plains to the mountain tops.
III. It ranges from subzero
levels in polar areas to >50°C in tropical deserts in summer.
IV. In deep hydrothermal vents and hot
springs, average temperatures exceed 100°C. Which of the statements given above are correct according
to the NCERT textbook?
224.Given below are two statements, one is labelled as Assertion (A) and the other is labelled as Reason
(R): Assertion (A): Mango trees do not and cannot grow in temperate countries like Canada and
Germany.
Reason (R): Snow leopards are commonly found in the deciduous forests of Kerala to regulate
local herbivore populations.
In the light of the above statements, choose the correct answer:
(R): Assertion (A): Mango trees do not and cannot grow in temperate countries like Canada and
Germany.
Reason (R): Snow leopards are commonly found in the deciduous forests of Kerala to regulate
local herbivore populations.
In the light of the above statements, choose the correct answer:
225.Consider the following statements regarding the thermal constraints on marine life and cellular
biochemistry: I. Tuna fish are rarely caught beyond tropical latitudes in the ocean.
II. Temperature affects
the kinetics of enzymes and through it the metabolic activity and other physiological functions of the
organism.
III. Eurythermal organisms can tolerate and thrive in a wide range of temperatures.
IV.
Stenothermal organisms are restricted to a narrow range of temperatures. Which of the statements given
above are correct according to the NCERT textbook?
biochemistry: I. Tuna fish are rarely caught beyond tropical latitudes in the ocean.
II. Temperature affects
the kinetics of enzymes and through it the metabolic activity and other physiological functions of the
organism.
III. Eurythermal organisms can tolerate and thrive in a wide range of temperatures.
IV.
Stenothermal organisms are restricted to a narrow range of temperatures. Which of the statements given
above are correct according to the NCERT textbook?
226.Given below are two statements, one is labelled as Assertion (A) and the other is labelled as Reason
(R): Assertion (A): The geographical distribution of many species is highly dependent on their thermal
tolerance limits.
Reason (R): A vast majority of organisms are eurythermal, allowing them to expand
across diverse climates.
In the light of the above statements, choose the correct answer:
(R): Assertion (A): The geographical distribution of many species is highly dependent on their thermal
tolerance limits.
Reason (R): A vast majority of organisms are eurythermal, allowing them to expand
across diverse climates.
In the light of the above statements, choose the correct answer:
227.Consider the following statements regarding water availability and salt concentrations in different
aquatic systems: I. Water is the next most important environmental factor after temperature.
II. Life on
earth originated in water and is unsustainable without water.
III. The salt concentration (measured as
salinity in parts per thousand) is less than 5 in inland waters.
IV. The salinity is 30-35 in the sea and >100
in some hypersaline lagoons. Which of the statements given above are correct according to the NCERT
textbook?
aquatic systems: I. Water is the next most important environmental factor after temperature.
II. Life on
earth originated in water and is unsustainable without water.
III. The salt concentration (measured as
salinity in parts per thousand) is less than 5 in inland waters.
IV. The salinity is 30-35 in the sea and >100
in some hypersaline lagoons. Which of the statements given above are correct according to the NCERT
textbook?
228.Given below are two statements, one is labelled as Assertion (A) and the other is labelled as Reason
(R): Assertion (A): Freshwater animals cannot live for long in sea water and vice versa.
Reason (R): They
would face severe osmotic problems in habitats with mismatched salinities. In the light of the above
statements, choose the correct answer:
(R): Assertion (A): Freshwater animals cannot live for long in sea water and vice versa.
Reason (R): They
would face severe osmotic problems in habitats with mismatched salinities. In the light of the above
statements, choose the correct answer:
229.Consider the following statements regarding the role of light in plant and animal physiology: I.
Since plants produce food through photosynthesis, a process which is only possible when sunlight is
available as a source of energy, we can understand the importance of light.
II. Many species of small
plants (herbs and shrubs) growing in forests are adapted to photosynthesise optimally under very low
light conditions.
III. These small forest plants are adapted to low light because they are constantly
overshadowed by a tall, canopied canopy of trees.
IV. Many plants are dependent on sunlight to meet their
photoperiodic requirement for flowering. Which of the statements given above are correct according to
the NCERT textbook?
Since plants produce food through photosynthesis, a process which is only possible when sunlight is
available as a source of energy, we can understand the importance of light.
II. Many species of small
plants (herbs and shrubs) growing in forests are adapted to photosynthesise optimally under very low
light conditions.
III. These small forest plants are adapted to low light because they are constantly
overshadowed by a tall, canopied canopy of trees.
IV. Many plants are dependent on sunlight to meet their
photoperiodic requirement for flowering. Which of the statements given above are correct according to
the NCERT textbook?
230.Given below are two statements, one is labelled as Assertion (A) and the other is labelled as Reason
(R): Assertion (A): The spectral quality of solar radiation is ecologically important for organisms,
especially marine plants living at depth.
Reason (R): Different components of the visible spectrum
penetrate to different depths in the ocean, with the red light component penetrating the deepest. In the
light of the above statements, choose the correct answer:
(R): Assertion (A): The spectral quality of solar radiation is ecologically important for organisms,
especially marine plants living at depth.
Reason (R): Different components of the visible spectrum
penetrate to different depths in the ocean, with the red light component penetrating the deepest. In the
light of the above statements, choose the correct answer:
231.Consider the following statements regarding the physical and chemical properties of soil that
dictate vegetation types: I. The nature and properties of soil in different places vary; it is dependent on the
climate, the weathering process, and whether soil is transported or sedimentary.
II. Various characteristics
of the soil such as soil composition, grain size and aggregation determine the percolation and water
holding capacity of the soils.
III. These soil characteristics, along with parameters such as pH, mineral
composition and topography, determine to a large extent the vegetation in any area.
IV. The soil
parameters are completely uniform across all biomes of the world, having no impact on plant types.
Which of the statements given above are correct according to the NCERT textbook?
dictate vegetation types: I. The nature and properties of soil in different places vary; it is dependent on the
climate, the weathering process, and whether soil is transported or sedimentary.
II. Various characteristics
of the soil such as soil composition, grain size and aggregation determine the percolation and water
holding capacity of the soils.
III. These soil characteristics, along with parameters such as pH, mineral
composition and topography, determine to a large extent the vegetation in any area.
IV. The soil
parameters are completely uniform across all biomes of the world, having no impact on plant types.
Which of the statements given above are correct according to the NCERT textbook?
232.Given below are two statements, one is labelled as Assertion (A) and the other is labelled as Reason
(R): Assertion (A): In the aquatic environment, the sediment characteristics largely determine the type of
benthic animals that can thrive there.
Reason (R): Benthic animals feed exclusively on the silica grains
that determine the physical grain size of the sediment. In the light of the above statements, choose the
correct answer:
(R): Assertion (A): In the aquatic environment, the sediment characteristics largely determine the type of
benthic animals that can thrive there.
Reason (R): Benthic animals feed exclusively on the silica grains
that determine the physical grain size of the sediment. In the light of the above statements, choose the
correct answer:
233.Consider the following statements regarding the concept of homeostasis and organism response to
abiotic stress: I. The organism should try to maintain the constancy of its internal environment
(homeostasis).
II. Homeostasis must be maintained despite varying external environmental conditions.
III.
Constant internal temperature and constant osmotic concentration are two key parameters of
homeostasis.
IV. Homeostasis represents the state where the internal temperature fluctuates
synchronously with the external temperature. Which of the statements given above are correct according
to the NCERT textbook?
abiotic stress: I. The organism should try to maintain the constancy of its internal environment
(homeostasis).
II. Homeostasis must be maintained despite varying external environmental conditions.
III.
Constant internal temperature and constant osmotic concentration are two key parameters of
homeostasis.
IV. Homeostasis represents the state where the internal temperature fluctuates
synchronously with the external temperature. Which of the statements given above are correct according
to the NCERT textbook?
234.Given below are two statements, one is labelled as Assertion (A) and the other is labelled as Reason
(R): Assertion (A): Ecologists use the analogy of a person maintaining 25°C in a car or room to explain
human homeostasis.
Reason (R): Humans maintain homeostasis strictly by using external mechanical air
conditioners rather than physical metabolic regulations. In the light of the above statements, choose the
correct answer:
(R): Assertion (A): Ecologists use the analogy of a person maintaining 25°C in a car or room to explain
human homeostasis.
Reason (R): Humans maintain homeostasis strictly by using external mechanical air
conditioners rather than physical metabolic regulations. In the light of the above statements, choose the
correct answer:
235.Consider the following statements regarding the physiological responses of 'Regulators' to abiotic
stress: I. Some organisms are able to maintain homeostasis by physiological (and sometimes behavioural)
means.
II. Regulators maintain constant body temperature and constant osmotic concentration.
III. All
birds and mammals, and a very few lower vertebrates and invertebrate species, are capable of regulation.
IV. The evolutionary success of mammals is largely due to their ability to maintain a constant body
temperature. Which of the statements given above are correct according to the NCERT textbook?
stress: I. Some organisms are able to maintain homeostasis by physiological (and sometimes behavioural)
means.
II. Regulators maintain constant body temperature and constant osmotic concentration.
III. All
birds and mammals, and a very few lower vertebrates and invertebrate species, are capable of regulation.
IV. The evolutionary success of mammals is largely due to their ability to maintain a constant body
temperature. Which of the statements given above are correct according to the NCERT textbook?
236.Given below are two statements, one is labelled as Assertion (A) and the other is labelled as Reason
(R): Assertion (A): An overwhelming majority (99 per cent) of animals and nearly all plants cannot
maintain a constant internal environment.
Reason (R): Thermoregulation is energetically expensive for
many organisms, especially small animals like shrews and hummingbirds. In the light of the above
statements, choose the correct answer:
(R): Assertion (A): An overwhelming majority (99 per cent) of animals and nearly all plants cannot
maintain a constant internal environment.
Reason (R): Thermoregulation is energetically expensive for
many organisms, especially small animals like shrews and hummingbirds. In the light of the above
statements, choose the correct answer:
237.Consider the following statements regarding the thermodynamic constraints on small-sized
endothermic animals: I. Heat loss or heat gain is a function of surface area.
II. Small animals have a larger
surface area relative to their volume.
III. Because of their large surface area to volume ratio, small
animals tend to lose body heat very fast when it is cold outside.
IV. Small animals are commonly found in
polar regions because their large surface area accelerates heat absorption from snow. Which of the
statements given above are correct according to the NCERT textbook?
endothermic animals: I. Heat loss or heat gain is a function of surface area.
II. Small animals have a larger
surface area relative to their volume.
III. Because of their large surface area to volume ratio, small
animals tend to lose body heat very fast when it is cold outside.
IV. Small animals are commonly found in
polar regions because their large surface area accelerates heat absorption from snow. Which of the
statements given above are correct according to the NCERT textbook?
238.Given below are two statements, one is labelled as Assertion (A) and the other is labelled as Reason
(R): Assertion (A): Every winter, the famous Keoladeo National Park in Bharatpur hosts thousands of
migratory birds.
Reason (R): The migratory birds fly in from Siberia and other extremely cold northern
regions to escape the harsh winter.
In the light of the above statements, choose the correct answer:
(R): Assertion (A): Every winter, the famous Keoladeo National Park in Bharatpur hosts thousands of
migratory birds.
Reason (R): The migratory birds fly in from Siberia and other extremely cold northern
regions to escape the harsh winter.
In the light of the above statements, choose the correct answer:
239.Consider the following statements regarding the diverse 'Suspend' strategies evolved by different
organisms under seasonal stress: I. Bears undergo hibernation during winter to escape cold stress.
II.
Some snails and fish undergo aestivation in summer to avoid heat and desiccation.
III. Under unfavorable
conditions, many zooplankton species in lakes and ponds are known to enter diapause.
IV. Diapause is
defined as a stage of suspended development. Which of the statements given above are correct according
to the NCERT textbook?
organisms under seasonal stress: I. Bears undergo hibernation during winter to escape cold stress.
II.
Some snails and fish undergo aestivation in summer to avoid heat and desiccation.
III. Under unfavorable
conditions, many zooplankton species in lakes and ponds are known to enter diapause.
IV. Diapause is
defined as a stage of suspended development. Which of the statements given above are correct according
to the NCERT textbook?
240.Given below are two statements, one is labelled as Assertion (A) and the other is labelled as Reason
(R): Assertion (A): In bacteria, fungi, and lower plants, various kinds of thick-walled spores are formed
under unfavorable conditions.
Reason (R): These thick-walled spores reduce metabolic activity to zero,
allowing the organism to immediately reproduce inside the dormant spore coat. In the light of the above
statements, choose the correct answer:
(R): Assertion (A): In bacteria, fungi, and lower plants, various kinds of thick-walled spores are formed
under unfavorable conditions.
Reason (R): These thick-walled spores reduce metabolic activity to zero,
allowing the organism to immediately reproduce inside the dormant spore coat. In the light of the above
statements, choose the correct answer:
Answer Key
11
23
33
43
51
61
73
81
93
101
114
122
131
144
154
164
174
183
194
203
211
221
232
242
254
264
274
282
294
304
314
323
333
344
354
361
374
382
391
401
411
422
432
442
452
463
471
483
493
502
512
521
532
541
554
561
574
584
591
601
614
622
632
642
654
664
672
682
694
701
711
721
733
744
751
764
771
784
793
804
812
823
832
843
853
864
872
884
891
904
911
922
934
943
953
963
971
982
993
1003
1014
1021
1033
1042
1051
1064
1074
1083
1093
1102
1111
1122
1131
1141
1154
1163
1174
1181
1192
1203
1214
1224
1232
1244
1254
1262
1271
1283
1292
1303
1314
1321
1331
1344
1354
1364
1371
1383
1391
1404
1413
1421
1431
1441
1454
1464
1471
1484
1493
1502
1511
1521
1531
1544
1551
1563
1572
1581
1594
1604
1612
1624
1632
1641
1651
1661
1672
1681
1693
1702
1712
1723
1731
1744
1751
1761
1773
1781
1792
1804
1812
1821
1833
1843
1852
1862
1871
1881
1891
1904
1911
1924
1932
1944
1951
1961
1972
1984
1991
2001
2014
2021
2032
2043
2053
2062
2071
2083
2091
2101
2112
2121
2131
2141
2154
2161
2173
2182
2192
2204
2214
2224
2231
2242
2251
2262
2274
2281
2293
2304
2311
2323
2333
2341
2352
2364
2374
2383
2393
2403