NCERT - Organisms and Populations Questions and Answers of Class 12 Biology | GkSeries

Questions
16 In a population, if the rate of addition of new members is higher than the rate of individuals lost, it shows
1 Exponential growth
2 Declined growth
3 Zero population growth
4 none of these

Answer: Exponential growth
17 Animals that have adapted themselves to live in deserts are known as
1 Fossorial
2 Xerocoles
3 Arboreal
4 Terrestrial

Answer: Xerocoles
18 Which of the followings take part in symbiosis of lichen?
1 Fungus-Fungus
2 Alga-Alga
3 Alga-Fungus
4 Fungus-Gymnosperm

Answer: Alga-Fungus
19 Ultraviolet radiation which is not lethal but harm to the organism is
1 0.1 to 0.28 µm
2 0.28-0.32 µm
3 0.32-0.4 µm
4 0.4-0.5 µm

Answer: 0.28-0.32 µm
20 In an ecosystem Biotic factors affect the survival of an organism in that ecosystem. They include
1 competition for food and water
2 competition for shelter
3 co-operation to help find food
4 All of these

Answer: All of these
21 Association between sea Anemone and Hermit crab in gastropod shell is that of
1 Parasitism
2 Commensalism
3 Symbiosis
4 Amensalism

Answer: Commensalism
22 Plant succession occurring in a sandy area is
1 Xerosere
2 Halosere
3 Psammosere
4 Hydrosere

Answer: Psammosere
23 Which one of the following is categorized as a parasite in true sense?
1 The cuckoo lays its egg in crow's nest
2 The female Anopheles bites and sucks blood from humans
3 Human foetus developing inside the uterus draws nourishment from the mother
4 Head louse living on the human scalp as well as laying eggs on human hair

Answer: Head louse living on the human scalp as well as laying eggs on human hair
24 Ecological niche of an organism represents
1 The resource it utilizes
2 Functional role in the ecological system
3 The range of conditions that it can tolerate
4 all of these

Answer: all of these
25 Respiratory roots are known as
1 velamen
2 pneumatophores
3 hydathodes
4 prop roots

Answer: pneumatophores
26 The maximum amount of water that a soil can hold, by capillary action is called
1 Wilting point
2 Water potential
3 Field capacity
4 Osmotic potential

Answer: Field capacity
27 A population with equal number of births and deaths will show
1 Acceleration phase of growth
2 Plateau phase
3 Exponential growth phase
4 Initial phase of growth

Answer: Plateau phase
28 Biotic potential is increase in population under
1 Optimum conditions
2 Climatic conditions
3 Natural conditions
4 Given conditions

Answer: Optimum conditions
29 In ecological succession from pioneer to climax community, the biomass shell
1 No relation
2 Increase and then decrease
3 Decrease
4 Increase continuously

Answer: Increase continuously
30 . The gradual physiological adjustment to slowly changing new environmental conditions is known as
1 Selection
2 Introduction
3 Acclimatization
4 Quarantine

Answer: Acclimatization

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