2013 GS Paper I, all questions

UPSC Prelims 2013 · GS Paper I

Question 31: Environment and Ecology

With reference to food chains in ecosystems, consider the following statements :

  1. 1.A food chain illustrates the order in which a chain of organisms feed upon each other.
  2. 2.Food chains are found within the populations of a species.
  3. 3.A food chain illustrates the numbers of each organism which are eaten by others.

Which of the statements given above is/are correct?

a1 only
b1 and 2 only
c1, 2 and 3
dNone

AnswerUPSC’s answer is (a).

A food chain shows the order of feeding, who eats whom, from producers up to top consumers, across different species in an ecosystem. It does not occur within the population of one species, and it does not show how many individuals are eaten; numbers are shown by a pyramid of numbers, not by the chain itself. Only statement 1 is correct.

  • 1. A food chain shows who feeds on whom in order.
  • 2. Food chains link different species, not members of a single population.
  • 3. Numbers eaten are shown by pyramids of numbers or energy, not by the chain.
Why each option is right or wrong
  • (a) Correct. A food chain shows the order in which organisms feed on each other.
  • (b) Wrong. Food chains link different species, not members of one population.
  • (c) Wrong. Statements 2 and 3 are both false.
  • (d) Wrong. Statement 1 is correct.

Answer: UPSC’s key. Explanation: written by UPSC Grade, not by UPSC.

Practise this paper timedPrevious questionNext question

Source: UPSC, Civil Services (Preliminary) Examination 2013, General Studies Paper I, Series A. The paper on upsc.gov.in.