2024 GS Paper I, all questions

UPSC Prelims 2024 · GS Paper I

Question 17: Environment and Ecology

With reference to perfluoroalkyl and polyfluoroalkyl substances (PFAS) that are used in making many consumer products, consider the following statements :

  1. 1.PFAS are found to be widespread in drinking water, food and food packaging materials.
  2. 2.PFAS are not easily degraded in the environment.
  3. 3.Persistent exposure to PFAS can lead to bioaccumulation in animal bodies.

Which of the statements given above are correct ?

a1 and 2 only
b2 and 3 only
c1 and 3 only
d1, 2 and 3

AnswerUPSC’s answer is (d).

PFAS are man-made 'forever chemicals' used in non-stick cookware, food packaging, fire-fighting foams and waterproof fabrics. They are widely found in drinking water, food and packaging. Their strong carbon-fluorine bonds resist breakdown, so they persist in the environment, and continued exposure lets them build up in the bodies of animals and humans. All three statements are correct.

  • 1. PFAS are widespread in drinking water, food and food packaging.
  • 2. PFAS do not break down easily and persist in the environment.
  • 3. Continued exposure leads to bioaccumulation in animal bodies.

How you could have got this

  1. If you were sure statement 1 is correct, (b) goes: it leaves 1 out.

    What you needed to know: PFAS are widespread in drinking water, food and food packaging.

  2. Then, if you were sure statement 2 is correct, (c) goes: it leaves 2 out.

    What you needed to know: PFAS do not break down easily and persist in the environment.

  3. Then, if you were sure statement 3 is correct, (a) goes: it leaves 3 out.

    What you needed to know: Continued exposure leads to bioaccumulation in animal bodies.

Only (d) is left. This one needs every statement.

Which options go is worked out from UPSC’s key and the options, not by a model.

Why each option is right or wrong
  • (a) Wrong: Statement 3 on bioaccumulation is also correct.
  • (b) Wrong: Statement 1 on their spread in water, food and packaging is also correct.
  • (c) Wrong: Statement 2 on persistence is also correct.
  • (d) Right: all three statements are correct.

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

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Source: UPSC, Civil Services (Preliminary) Examination 2024, General Studies Paper I, Series A. The paper on upsc.gov.in.