1997 General Studies, all questions

UPSC Prelims 1997 · General Studies

Question 104: Geography

Which one of the following is present in the largest amount in terms of per cent by mass in the earth’s crust?

aSilicon
bOxygen
cCarbon
dCalcium

AnswerThe answer is (b).

Oxygen makes up about 46 per cent of the earth's crust by mass, mostly locked in silicate and oxide minerals. Silicon comes second at about 28 per cent, followed by aluminium and iron. Calcium is only a few per cent, and carbon is a very small fraction.

Why each option is right or wrong
  • (a) Silicon is second, at about 28 per cent.
  • (b) Right: oxygen.
  • (c) Carbon is a very small fraction of the crust.
  • (d) Calcium is only a few per cent of the crust.

Explanation: written by UPSC Grade, not by UPSC.

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Source: UPSC, Civil Services (Preliminary) Examination 1997, General Studies. UPSC's own paper isn't online; the words are from a published compilation. The paper on upsc.gov.in.