Consider the following statements : Statement I : Scientific studies suggest that a shift is taking place in the Earth's rotation and axis. Statement II : Solar flares and associated coronal mass ejections bombarded the Earth's outermost atmosphere with tremendous amount of energy. Statement III : As the Earth's polar ice melts, the water tends to move towards the equator. Which one of the following is correct in respect of the above statements?
- (a) Both Statement II and Statement III are correct and both of them explain Statement I
- (b) Both Statement II and Statement III are correct but only one of them explains Statement I ✓ UPSC's answer
- (c) Only one of the Statements II and III is correct and that explains Statement I
- (d) Neither Statement II nor Statement III is correct
Why the answer is (b)
• Studies using satellite and GRACE gravity data show the Earth's rotation axis (the 'pole') has drifted measurably in recent decades — statement I is correct.
• Statement II is a true description of space weather: solar flares and coronal mass ejections do dump enormous energy into the upper atmosphere, but this affects the ionosphere and satellites, not the planet's mass distribution or spin axis; it does not explain I.
• Statement III is correct and explanatory: as polar ice sheets melt, the water spreads towards the equator and, together with groundwater depletion, shifts mass away from the poles, altering the rotation axis and slightly lengthening the day.
• So both II and III are true, but only III explains the shift in rotation and axis.
• Hence option (b).
Why the other options are wrong
- (a) Both Statement II and Statement III are correct and both of them explain Statement I
- Statement II, though true, does not explain the axis shift; only mass redistribution (III) does.
- (c) Only one of the Statements II and III is correct and that explains Statement I
- Both II and III are factually correct.
- (d) Neither Statement II nor Statement III is correct
- Both II and III are correct statements.
Asked in the GS Paper I of the UPSC Civil Services Preliminary Examination 2025, held on 25 May 2025. Question and answer key: Union Public Service Commission. Explanation: UPSC Answer Check.