Class 10 Science

Our Environment

NCERT Exemplar Problems

MCQs Part 1

Question 1: Which one of the following is an artificial ecosystem?

  1. Pond
  2. Crop field
  3. Lake
  4. Forest

    Answer: (b) Crop field

Question 2: In a food chain, the third trophic level is always occupied by

  1. Carnivores
  2. Herbivores
  3. Decomposers
  4. Producers

    Answer: (a) Carnivores

Question 3: An ecosystem includes

  1. All living organisms
  2. Non-living objects
  3. Both living organisms and non-living objects
  4. Sometimes living organisms and sometimes non-living objects

    Answer: (c) Both living organisms and non-living objects

Question 4: In the given food chain, suppose the amount of energy at fourth trophic level is 5 kJ, what will be the energy available at the producer level?
Grass ↠ Grasshopper ↠ Frog ↠ Snake ↠ Hawk

  1. 5 k J
  2. 50 k J
  3. 500 k J
  4. 5000 k J

    Answer: (d) 5000 kJ

Question 5: Accumulation of non-biodegradable pesticides in the food chain in increasing amount at each higher trophic level is known as

  1. Eutrophication
  2. Pollution
  3. Biomagnification
  4. Accumulation

    Answer: (c) Biomagnification

Question 6: Depletion of ozone is mainly due to

  1. Chlorofluorocarbon compounds
  2. Carbon monoxide
  3. Methane
  4. Pesticides

    Answer: (a) Chlorofluorocarbon compounds

Question 7: Organisms which synthesise carbohydrates from inorganic compounds using radiant energy are called

  1. Decomposers
  2. Producers
  3. Herbivores
  4. Carnivores

    Answer: (b) Producers

Question 8: In an ecosystem, the 10% of energy available for transfer from one trophic level to the next is in the form of

  1. Heat energy
  2. Light energy
  3. Chemical energy
  4. Mechanical energy

    Answer: (c) Chemical energy

Question 9: Organisms of a higher trophic level which feed on several types of organisms belonging to a lower trophic level constitute the

  1. Food web
  2. Ecological pyramid
  3. Ecosystem
  4. Food chain

    Answer: (b) Ecological pyramid

Question 10: Flow of energy in an ecosystem is always

  1. Unidirectional
  2. Bidirectional
  3. Multi directional
  4. No specific direction

    Answer: (a) Unidirectional

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