CBSE Class 12 Biology Organisms and Populations MCQs Set 03

Question. Niche overlap indicates
(a) mutualism between two species
(b) active cooperation between two species
(c) two different parasites on the same host
(d) sharing of one or more resources between the two species.

Answer : D

Question. Praying mantis is a good example of
(a) camouflage
(b) mullerian mimicry
(c) warning colouration
(d) social insects.

Answer : A

Question. Mycorrhizae are the example of
(a) amensalism
(b) antibiosis
(c) mutualism
(d) fungistasis.

Answer : C

Question. Obligate parasites live on
(a) living host only
(b) living host and dead organic matter
(c) dead organic matter only
(d) artificial liquid medium

Answer : A

Question. In which of the following interactions both partnersare adversely affected?
(a) Parasitism
(b) Mutualism
(c) Competition
(d) Predation

Answer : C

Question. Which one of the following is a matching pair of certain organism(s) and the kind of association?
(a) Shark and sucker fish – Commensalism
(b) Algae and fungi in lichens – Mutualism
(c) Orchids growing on trees – Parasitism
(d) Cuscuta (dodder) growing on other -flowering plants – Epiphytism

Answer : B

Question. Which one of the following is not a parasitic adaptation?
(a) Development of adhesive organs
(b) Loss of digestive organs
(c) Loss of reproductive capacity
(d) Loss of unnecessary sense organs

Answer : C

Question. Niche overlap indicates
(a) mutualism between two species
(b) active cooperation between two species
(c) two different parasites on the same host
(d) sharing of one or more resources between the two species.

Answer : D

Question. When does the growth rate of a population following the logistic model equal zero? The logistic model is given as dN/dt = rN(1–N/K)
(a) when N/K equals zero
(b) when death rate is greater than birth rate
(c) when N/K is exactly one
(d) when N nears the carrying capacity of the habitat.

Answer : C

Question. Certain characteristic demographic features of developing countries are
(a) high fertility, low or rapidly falling mortality rate, rapid population growth and a very young age distribution
(b) high fertility, high density, rapidly rising mortality rate and a very young age distribution
(c) high infant mortality, low fertility, uneven population growth and a very young age distribution
(d) high mortality, high density, uneven population growth and a very old age distribution.

Answer : A

Question. Large woody vines are more commonly found in
(a) temperate forests
(b) mangroves
(c) tropical rainforests
(d) alpine forests.

Answer : C

Question. Reduction in vascular tissue, mechanical tissue and cuticle is characteristic of
(a) mesophytes
(b) epiphytes
(c) hydrophytes
(d) xerophytes.

Answer : C

Question. In which of the following plant sunken stomata are found?
(a) Nerium
(b) Hydrilla
(c) Mango
(d) Guava

Answer : A

Question. A population of 500 that experiences 55 births and 5 deaths during a one-year period. What is the reproductive rate for the population during the one-year period ?
(a) 0.01/year
(b) 0.05/year
(c) 0.1/year
(d) 50/year

Answer : C

Question. Besides paddy fields, cyanobacteria are also found inside vegetative part of
(a) Equisetum
(b) Psilotum
(c) Pinus
(d) Cycas.

Answer : D

Question. Carnivorous animals lions and leopards, occupy the same niche but lions predate mostly larger animals and leopards take smaller ones. This mechanism of competition is referred to as
(a) character displacement
(b) altruism
(c) resource partitioning
(d) competitive exclusion.

Answer : C

Question. Geometric representation of age structure is a characteristic of
(a) population
(b) landscape
(c) ecosystem
(d) biotic community.

Answer : A

Question. Which one of the following is categorised as a parasite in true sense?
(a) The female Anopheles bites and sucks blood from humans.
(b) Human fetus developing inside the uterus draws nourishment from the mother.
(c) Head louse living on the human scalp as well as laying eggs on human hair.
(d) The cuckoo (koel) lays its eggs in crow’s nest.

Answer : C

Question. The rate of formation of new organic matter by rabbit in a grassland, is called
(a) Net productivity
(b) Secondary productivity
(c) Net primary productivity
(d) Gross primary productivity

Answer : B

Question. Competition for light, nutrients and space is most severe between
(a) closely related organism growing in different niche
(b) closely related organisms growing in the same area/niche
(c) distantly related organisms growing in the same habitat
(d) distantly related organisms growing in different niches.

Answer : B

Question. Within biological communities, some species are important in determining the ability of a large number of other species to persist in the community. Such species are called
(a) keystone species
(b) allopatric species
(c) sympatric species
(d) threatened species

Answer : A

Question. Keystone species deserve protection because these
(a) are capable of surviving in harsh environmental conditions.
(b) indicate presence of certain minerals in thesoil.
(c) have become rare due to overexploitation.
(d) play an important role in supporting other species.

Answer : D