CBSE Class 12 Biology Organisms and Populations MCQs Set B

Question. Pneumatophores occur in
(a) halophytes
(b) free-floating hydrophytes
(c) carnivorous plants
(d) submerged hydrophytes.

Answer : A

Question. An association of individuals of different species living in the same habitat and having functional interactions is
(a) ecosystem
(b) population
(c) ecological niche
(d) biotic community.

Answer : D

Question. Which of the following communities is more vulnerable to invasion by outside animals and plants?
(a) Temperate forests
(b) Oceanic island communities
(c) Mangroves
(d) Tropical evergreen forests

Answer : D

Question. The sum total of the populations of the same kind of organisms constitute
(a) colony
(b) genus
(c) community
(d) species.

Answer : D

Question. The maintenance of internal favourable conditions, by a self regulated mechanisms inspite of the fact that there are changes in environment, is known as
(a) entropy
(b) enthalpy
(c) homoeostasis
(d) steady state

Answer : C

Question. The age pyramid with broad base indicates
(a) high percentage of old individuals
(b) low percentage of young individuals
(c) a stable population
(d) high percentage of young individuals.

Answer : D

Question. Mycorrhiza exhibits the phenomenon of
(a) parasitism
(b) symbiosis
(c) antagonism
(d) endemism.

Answer : B

Question. Which one is true?
(a) Commensalism when none of the interacting populations affect each other.
(b) Symbiosis when the interaction is useful to both the populations.
(c) Symbiosis when neither populations affects each other.
(d) Commensalism when the interaction is useful to both the populations.

Answer : B

Question. In Urn shaped age pyramid of the population the trend of growth is
(a) Rapid
(b) Stable
(c) Declining
(d) Stationary

Answer : C

Question. Plants such as Prosopis, Acacia and Capparis represent examples of tropical
(a) deciduous forests
(b) evergreen forests
(c) grasslands
(d) thorn forests.

Answer : D

Question. Mycorrhiza is an example of
(a) symbiotic relationship
(b) ectoparasitism
(c) endoparasitism
(d) decomposers.

Answer : A

Question. Which type of association is found in between entomophilous flower and pollinating agent?
(a) Mutualism
(b) Commensalism
(c) Co-operation
(d) Co-evolution

Answer : D

Question. Animals have the innate ability to escape from predation. Examples for the same are given below. Select the incorrect example.
(a) Colour change in Chamaeleon
(b) Enlargement of body size by swallowing air in puffer fish
(c) Poison fangs in snakes
(d) Melanism in moths

Answer : C

Question. In which one of the following habitats does the diurnal temperature of soil surface vary most?
(a) Shrub land
(b) Forest
(c) Desert
(d) Grassland

Answer : C

Question. Homeostasis is
(a) tendency of biological systems to change with change in environment
(b) tendency of biological systems to resist change
(c) disturbance of self regulatory system and natural controls
(d) biotic materials used in homeopathic medicines

Answer : B

Question. Which one of the following plants shows a very close relationship with a species of moth, where none of the two can complete its life cycle without the other?
(a) Hydrilla
(b) Yucca
(c) Banana
(d) Viola

Answer : B

Directions : In the following questions a statement of Assertion (A) is followed by a statement of reason (R). Mark the correct choice as :
(A) Both Assertion (A) and reason (R) are true and reason (R) is the correct explanation of Assertion (A).
(B) Both Assertion (A) and reason (R) are true but reason (R) is not the correct explanation of Assertion (A).
(C) Assertion (A) is true but reason (R) is false.
(D) Assertion (A) is false but reason (R) is true.

Question. Assertion (A) : Some organisms like Salmon are known as Euryhaline.
Reason (R) : Euryhalines can tolerate a wide range of salinities.

Answer : A

Read the following text and answer the following questions on the basis of the same :
Population is a group of individuals of a single species living in a given area. It includes spatial arrangement, genetic variation and the dynamics including natality, mortality, biotic potential, carrying capacity, etc. Population structure includes features such as density, abundance, spacing,genetic variations. The genetic structure reveals genetic variations and population size.

Question. ______ is the study of the ecology of population.
(A) Autecology
(B) Demecology
(C) Endaphology
(D) None of the above

Answer : B

Question. Which Indian state has the least population growth?
(A) Kerala
(B) U.P.
(C) A.P.
(D) Assam.

Answer : A

Question. There is more competition for survival between :
(A) Different animals of same niche.
(B) Same animals of same niche.
(C) Different animals of different niche.
(D) Same animals of different niche.

Answer : B

Question. ______ species inhabit different geographical areas. 1
(A) Sympatic
(B) Allopatric
(C) Both (A) and (B)
(D) None of these

Answer : B

Question. Increase in population does not increase in :
(A) Health facilities
(B) Employment
(C) Food resources
(D) All of the above

Answer : D