#14 Biology Class XII- Ecosystem (NEET, MHTCET) MCQ
1) Mass of living matter at a trophic level in an area at any time is called
(a) standing crop
(b) detritus
(c) humus
(d) standing state
Answer
(a) standing crop
2) Which one of the following is not a gaseous biogeochemical cycle in ecosystem?
(a) Oxygen cycle
(b) Phosphorus cycle
(c) Nitrogen cycle
(d) Carbon cycle
Answer
(b) Phosphorus cycle
3) Identify the possible link “A” in the following food chain.
Plant → insect → frog → “A” → eagle
(a) rabbit
(b) wolf
(c) cobra
(d) parrot
Answer
(c) cobra
4) Which one of the following is not a functional unit of an ecosystem?
(a) Energy flow
(b) Decomposition
(c) Productivity
(d) Stratification
Answer
(d) Stratification
5) The upright pyramid of number is absent in
(a) pond
(b) forest
(c) lake
(d) grassland
Answer
(b) forest
6) The rate of formation of new organic matter by rabbit in a grassland, is called
(a) net productivity
(b) second productivity
(c) net primary productivity
(d) gross primary productivity
Answer
(a) net productivity
7) Decomposers like fungi and bacteria are [NCERT Exemplar]
(i) autotrophs
(ii) heterotrophs
(iii) saprotrophs
(iv) chemo-autotrophs
(a) (i) and (iii)
(b) (i) and (iv)
(c) (ii) and (iii)
(d) (i) and (ii)
Answer
(c) (ii) and (iii)
8) The process of mineralisation by microorganisms helps in the release of [NCERT Exemplar]
(a) inorganic nutrients from humus
(b) both organic and inorganic nutrients from detritus
(c) organic nutrients from humus
(d) inorganic nutrients from detritus and formation of humus.
Answer
(a) inorganic nutrients from humus
9) Productivity is the rate of production of biomass expressed in terms of [NCERT Exemplar]
(i) (kcal m–3) yr–1
(ii) g–2 yr–1
(iii) g–1 yr–1
(iv) (kcal m–2) yr–1
(a) (ii)
(b) (iii)
(c) (ii) and (iv)
(d) (i) and (iii)
Answer
(c) (ii) and (iv)
10) An inverted pyramid of biomass can be found in which ecosystem? [NCERT Exemplar]
(a) Forest
(b) Marine
(c) Grass land
(d) Tundra
Answer
(b) Marine
11) What is the difference between a community or group of communities and an ecosystem?
(a) A community and the abiotic environment comprise an ecosystem.
(b) An ecosystem is a type of community.
(c) A biome includes only the plant community or communities present in an environment.
(d) An ecosystem includes only the abiotic aspects of a particular environment.
Answer
(a) A community and the abiotic environment comprise an ecosystem.
12) Which of the following ecosystems is most productive in terms of net primary production? [NCERT Exemplar]
(a) Deserts
(b) Tropical rain forests
(c) Oceans
(d) Estuaries
Answer
(b) Tropical rain forests
13) Pyramid of numbers is [NCERT Exemplar]
(a) always upright
(b) always inverted
(c) either upright or inverted
(d) neither upright nor inverted
Answer
(c) either upright or inverted
14) Of the total amount of energy that passes from one trophic level to another, about 10% is
(a) respired and becomes heat
(b) passed out as faces or urine
(c) stored as body tissue
(d) recycled to autotrophs
Answer
(c) stored as body tissue
15) During the process of ecological succession the changes that take place in communities are [NCERT Exemplar]
(a) orderly and sequential
(b) random
(c) very quick
(d) not influenced by the physical environment.
Answer
(a) orderly and sequential
16) Climax community is in a state of [NCERT Exemplar]
(a) non-equilibrium
(b) equilibrium
(c) disorder
(d) constant change.
Answer
(b) equilibrium
17) Among the following bio-geo-chemical cycles which one does not have losses due to respiration? [NCERT Exemplar]
(a) Phosphorus
(b) Nitrogen
(c) Sulphur
(d) All of the above
Answer
(d) All of the above
18) The sequence of communities of primary succession in water is [NCERT Exemplar]
(a) phytoplankton, sedges, free-floating hydrophytes, rooted hydrophytes, grasses and trees.
(b) phytoplankton, free-floating hydrophytes, rooted hydrophytes, sedges, grasses and trees.
(c) free-floating hydrophytes, sedges, phytoplankton, rooted hydrophytes, grasses and trees.
(d) phytoplankton, rooted submerged hydrophytes, floating hydrophytes, reed swamp, sedges, meadow and trees.
Answer
(b) phytoplankton, free-floating hydrophytes, rooted hydrophytes, sedges, grasses and trees.
19) The reservoir for the gaseous type of bio-geo chemical cycle exists in [NCERT Exemplar]
(a) stratosphere
(b) atmosphere
(c) ionosphere
(d) lithosphere
Answer
(b) atmosphere
20) If the carbon atoms fixed by producers already have passed through three species, the trophic level of the last species would be: [NCERT Exemplar]
(a) scavenger
(b) tertiary producer
(c) tertiary consumer
(d) secondary consumer
Answer
(c) tertiary consumer
21) Humans benefit from ecosystems because ecosystems provide
(a) buffers from natural disasters such as floods.
(b) maintenance of a clean water supply.
(c) climate moderation.
(d) All of the above
Answer
(d) All of the above
22) Which of the following type of ecosystem is expected in an area where evaporation exceeds precipitation, and mean annual rainfall is below 100 mm? [NCERT Exemplar]
(a) Grassland
(b) Shrubby forest
(c) Desert
(d) Mangrove
Answer
(c) Desert
23) The zone at the edge of a lake or ocean which is alternatively exposed to air and immersed in water is called: [NCERT Exemplar]
(a) pelagic zone
(b) benthic zone
(c) lentic one
(d) littoral zone
Answer
(d) littoral zone
24) Edaphic factor refers to: [NCERT Exemplar]
(a) water
(b) soil
(c) relative humidity
(d) altitude
Answer
(b) soil
25) Which of the following is an ecosystem service provided by a natural ecosystem? [NCERT Exemplar]
(a) Cycling of nutrients
(b) Prevention of soil erosion
(c) Pollutant absorption and reduction of the threat of global warming
(d) All of the above
Answer
(d) All of the above
26) A succession of communities on barren land, is known as
(a) secondary succession
(b) primary succession
(c) tertiary succession
(d) none of these
Answer
(b) primary succession
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