12th Standard CBSE - Biology - Ecosystem

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Question - 1

Which one of the following has the largest population in a food chain?

  • A Producers
  • B Primary consumers
  • C Secondary consumers
  • D Decomposers

Question - 2

Secondary producers are

  • A Herbivores
  • B Producers
  • C Carnivores
  • D None of these

Question - 3

Thye second trophic level in a lake is

  • A Phytoplankton
  • B Zooplankton
  • C Benthos
  • D Fishes

Question - 4

What is the percentage of photosynthetically active radiation (PAR) in the incident solar radiation?

  • A 100%
  • B 50%
  • C 1-5%
  • D 2-10%

Question - 5

Second most important trophic level in a lake is 

  • A Phytoplankton
  • B Zooplankton
  • C Benthas
  • D Fishes

Question - 6

Secondary producers are

  • A Herbivores
  • B Producers
  • C Carnivores
  • D None of the above

Question - 7

What is the percentage of photosynthetically active radiation (PAR), if incident solar radiation is considered 100%?

  • A 100%
  • B 50%
  • C 1-5%
  • D 2-10%

Question - 8

Which of the following is an abiotic component of the ecosystem?

  • A Bacteria
  • B Humus
  • C Plants
  • D Fungi

Question - 9

Which of the following process helps in nutrient conservation?

  • A Mineralisation
  • B Immobilisation
  • C Leaching
  • D Nitrification

Question - 10

What fraction of assimilated energy is used in respiration by the herbivore?

  • A 20 per cent
  • B 30 per cent
  • C 40 per cent
  • D 60 per cent