2019 GS Paper I, all questions

UPSC Prelims 2019 · GS Paper I

Question 34: Environment and Ecology

Which of the following statements are correct about the deposits of ‘methane hydrate’?

  1. 1.Global warming might trigger the release of methane gas from these deposits.
  2. 2.Large deposits of ‘methane hydrate’ are found in Arctic Tundra and under the seafloor.
  3. 3.Methane in atmosphere oxidizes to carbon dioxide after a decade or two.

Select the correct answer using the code given below.

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

AnswerUPSC’s answer is (d).

All three statements are correct. Methane hydrates are ice-like solids that trap methane, found in Arctic permafrost and tundra and under the seafloor along continental margins. Global warming could destabilise them and release methane, a potent greenhouse gas, which would add to further warming. In the atmosphere methane is oxidised to carbon dioxide over roughly a decade or two.

  • 1. Warming could destabilise hydrates and release methane.
  • 2. Hydrates occur in Arctic tundra and under the seafloor.
  • 3. Atmospheric methane oxidises to carbon dioxide within about a decade or two.

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: Warming could destabilise hydrates and release methane.

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

    What you needed to know: Hydrates occur in Arctic tundra and under the seafloor.

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

    What you needed to know: Atmospheric methane oxidises to carbon dioxide within about a decade or two.

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) Statement 3 is also correct.
  • (b) Statement 1 is also correct.
  • (c) Statement 2 is also correct.
  • (d) Correct: all three statements hold.

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

Practise this paper timedPrevious questionNext question

Source: UPSC, Civil Services (Preliminary) Examination 2019, General Studies Paper I, Series A. The paper on upsc.gov.in.