Class 12 Biology Chapter 14 MCQs (Ecosystems and Energy flow MCQ)
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Class 12 Biology Chapter 14 MCQs (Ecosystems and Energy flow MCQ)
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1. Which one of the following has the largest population in a food chain?
  a. Producers
  b. Primary consumers
  c. Secondary consumers
  d. Decomposers
Answer : Decomposers
Explanation :Decomposers include micro-organisms such as bacteria and fungi. They form the largest population in a food chain and obtain nutrients by breaking down the remains of dead plants and animals.
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2. The second trophic level in a lake is ________________
  a. Phytoplankton
  b. Zooplankton
  c. Benthos
  d. Fishes
Answer : zooplankton
Explanation :Zooplankton are primary consumers in aquatic food chains. They feed upon phytoplankton. They are present in the second trophic level. Hence, second most important trophic level in a lake is zooplankton.
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3. Secondary consumers are __________
  a. Herbivores
  b. Producers
  c. Carnivores
  d. Autotrophs
Answer : Carnivores
Explanation :Secondary consumers are usually carnviores (meat eaters) but can also be omnivores. Omnivorous consumers eat everything.
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4. What is the % of photosynthetically active radiation in the incident solar radiation?
  a. 100%
  b. 50 %
  c. 1-5%
  d. 2-10%
Answer : 50%
Explanation : Out of total incident solar radiation, about fifty percent of it forms photosynthetically active radiation or PAR.
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5. Give the term used to express a community in its final stage of succession?
  a. End community
  b. Final community
  c. Climax community
  d. Dark community
Answer : Climax community
Explanation:The term climax community is used to express a community in its final stage of succession. The climax community may change if there are changed in climate or long term evolutionary changes in species.
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6. After landslide which of the following type of succession occurs?
  a. Primary
  b. Secondary
  c. Tertiary
  d. Climax
Answer : Primary
Explanation: Succession is generally regarded as primary when it occurs on a landslide where rock and subsoil, virtually free of organic matter are exposed, despite the fact that landslide was formed the substratum just beneath a developed soil carrying vegetation.
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7. Which of the following is most often a limiting factor of the primary productivity in any ecosystem.
  a. Carbon
  b. Nitrogen
  c. Phosphorus
  d. Sulphur
Answer : Carbon
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