The meaning and definition of environment — MCQs

All questions with answers and explanations

Read the full set here, or use the practice card above to test yourself one question at a time.

1. Under Section 2(a) of the Environment (Protection) Act, 1986, 'environment' includes water, air, land and the inter-relationship between them and:

   • Only government property
   • Human beings, other living creatures, plants, micro-organisms and property (correct answer)
   • Only wildlife and forests
   • Only industrial establishments

   Explanation. Section 2(a) expressly includes human beings, other living creatures, plants, micro-organisms, and property in its definition of environment, alongside water, air, and land.

2. Who coined the term 'Ecology'?

   • Charles Darwin
   • Ernst Haeckel (correct answer)
   • Kautilya
   • Rachel Carson

   Explanation. German biologist Ernst Haeckel coined the term 'ecology' in 1866, from the Greek 'oikos' (habitat) and 'logos' (study).

3. Which of the following is the correct order of ecological levels of organisation, from smallest to largest?

   • Ecosystem → Population → Organism → Community
   • Organism → Population → Community → Ecosystem (correct answer)
   • Community → Ecosystem → Organism → Population
   • Population → Ecosystem → Organism → Community

   Explanation. The correct order is Organism (individual) → Population (same species in an area) → Community (all species in an area) → Ecosystem (community + physical environment).

4. In an ecosystem, which biotic component breaks down dead organic matter and recycles nutrients?

   • Producers
   • Consumers
   • Decomposers (correct answer)
   • Abiotic factors

   Explanation. Decomposers (fungi and bacteria) break down dead organic matter, recycling nutrients back into the ecosystem.

5. The flow of energy through an ecosystem, from sunlight to producers to consumers, is best described as:

   • Cyclical and reusable
   • Unidirectional and non-recyclable (correct answer)
   • Random and unpredictable
   • Reversible at any trophic level

   Explanation. Energy flow is unidirectional — it moves one way from sunlight through the trophic levels, and is lost as heat at each stage, unlike nutrients which are cycled and reused.

6. A single pond, with its water, fish, algae, and the sunlight and mud that support them, is an example of a/an:

   • Biome
   • Biosphere
   • Ecosystem (correct answer)
   • Population

   Explanation. An ecosystem can be as small as a single pond — what defines it is biotic and abiotic components interacting as a functional unit, not its size.

7. An ecosystem's ability to self-regulate and maintain overall stability despite ongoing changes is called:

   • Succession
   • Homeostasis (correct answer)
   • Biodiversity
   • Trespass

   Explanation. Homeostasis is an ecosystem's dynamic, ongoing self-regulating process to maintain balance — not a fixed, unchanging state.

8. Which statement correctly distinguishes Environment from Ecology?

   • They are exact synonyms with no difference
   • Environment is the surroundings itself; Ecology is the study of how organisms interact with it (correct answer)
   • Ecology is a branch of law; Environment is a branch of science
   • Environment only refers to air pollution

   Explanation. Environment is the subject matter (the surroundings themselves); Ecology is the scientific study of how organisms interact with those surroundings.