UPSC Prelims 2025 · GS Paper I
Question 25: Geography
Which of the following are the evidences of the phenomenon of continental drift?
- IThe belt of ancient rocks from Brazil coast matches with those from Western Africa.
- IIThe gold deposits of Ghana are derived from the Brazil plateau when the two continents lay side by side.
- IIIThe Gondwana system of sediments from India is known to have its counterparts in six different landmasses of the Southern Hemisphere.
Select the correct answer using the code given below.
AnswerThe answer is (c).
Alfred Wegener's theory of continental drift cites matching evidence across the Atlantic. Ancient rock belts about 2,000 million years old on the Brazilian coast match those of Western Africa. The gold deposits of Ghana have no known source rock in Africa and are believed to have come from the Brazilian plateau when the two continents were joined. Gondwana-system sediments of India have counterparts in six landmasses of the Southern Hemisphere. All three are cited as evidence.
- I. Old rock belts on the Brazilian coast match those of Western Africa.
- II. Ghana's gold is traced to the Brazilian plateau, when the continents lay side by side.
- III. Gondwana sediments are found in six southern landmasses, including India.
How you could have got this
- If you were sure statement I is correct, (d) goes: it leaves I out.
What you needed to know: Old rock belts on the Brazilian coast match those of Western Africa.
- Then, if you were sure statement II is correct, (a) goes: it leaves II out.
What you needed to know: Ghana's gold is traced to the Brazilian plateau, when the continents lay side by side.
- Then, if you were sure statement III is correct, (b) goes: it leaves III out.
What you needed to know: Gondwana sediments are found in six southern landmasses, including India.
Only (c) is left. This one needs every statement.
This follows an unofficial answer: UPSC has not published its key for this year, and if that answer is wrong, so is this path.
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: the Ghana gold deposits are also cited as evidence.
- (b) Wrong: the Gondwana sediments are also cited as evidence.
- (c) Right: matching rock belts, the Ghana gold deposits and the Gondwana sediments all support drift.
- (d) Wrong: the matching rock belts are also cited as evidence.
Explanation: written by UPSC Grade, not by UPSC.
Source: UPSC, Civil Services (Preliminary) Examination 2025, General Studies Paper I, Series A. The paper on upsc.gov.in.