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Environment & EcologyMediumAsked in: NDA · NDA-II 2023, GAT

The green plants in a terrestrial ecosystem absorbs sunlight that falls on their leaves and convert it into food energy. The percentage of solar radiation absorbed by all green plants for the process of photosynthesis is about

  1. A.1%
  2. B.5%
  3. C.8%
  4. D.10%

Correct answer

A. 1%

Explanation

The correct answer is A, 1%. Of all the sunlight that falls on their leaves, green plants fix only about one per cent as chemical energy in food.

Less than half of the incoming solar radiation is photosynthetically active radiation (PAR), light of about 400 to 700 nm, and plants capture only 2 to 10 per cent of that PAR. The rest is reflected, passes through the leaves or is lost as heat during transpiration. This small fraction is the gross primary productivity on which every food chain depends, and only about 10 per cent of the energy at one trophic level passes on to the next, as Lindeman's ten per cent law states.

B is wrong: 5 per cent is about five times the real share for green plants as a whole.

C is wrong: 8 per cent is many times higher than what green plants manage across an ecosystem.

D is wrong: 10 per cent is the energy passed between trophic levels, a figure often confused with this one.

Exam tip: plants fix about 1% of sunlight; about 10% of energy passes up each trophic level.

Practice Questions

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Q2.Environment & EcologyAsked in: CDS · CDS-I 2019, GKMedium

Which one of the following statements about the National Green Tribunal is not correct?

  1. A.It was set up in the year 2010.
  2. B.It is involved in effective and expeditious disposal of cases relating to environmental protection and conservation of forests.
  3. C.It may consider giving relief and compensation for damages to persons and property.
  4. D.It is bound by the procedures laid down under the Code of Civil Procedure, 1908.
Show answer
Correct answer: D. It is bound by the procedures laid down under the Code of Civil Procedure, 1908.

The National Green Tribunal is not bound by the Code of Civil Procedure; it is guided by the principles of natural justice.

Q3.Environment & EcologyAsked in: CDS · CDS-I 2018, GKHard

Consider the following statements about National Wildlife Action Plan (NWAP) of India for 2017-2031:

1. This is the Third National Wildlife Action Plan.

2. The NWAP is unique as this is the first time India has recognized the concerns relating to climate change impact on wildlife.

3. The NWAP has ten components.

Which of the statements given above is/are correct?

  1. A.1 only
  2. B.1 and 2 only
  3. C.2 and 3 only
  4. D.1, 2 and 3
Show answer
Correct answer: B. 1 and 2 only

The plan for 2017-2031 is India's third National Wildlife Action Plan and the first to deal with the impact of climate change on wildlife, but it has five components, not ten.