Explanation
- A
Both Statements II and III are correct and both of them explain Statement I
Both II and III correct and both explain I. Solar flares and CMEs dump energy into the thermosphere and ionosphere. They do not shift the rotation axis the way ice melt does. II is true as space weather; it does not explain I.
- B
Both Statement II and Statement III are correct but only one of them explains Statement I
Both II and III are correct but only one of them explains I. III is the explanation: meltwater from polar ice moves toward the equator, redistributes mass, and studies report a tiny polar-motion / length-of-day signal. II is correct space physics, not the cause of I.
- C
Only one of the Statement II and III is correct and that explains Statement I
Only one of II and III is correct. Both statements hold; only the explanation link is one-way.
- D
Neither Statement II nor Statement III is correct
Neither. Ice-mass shift is the standard geophysics line for I.
Summary. Official key is (b): solar flares (II) and meltwater moving toward the equator (III) are both real, but only ice-mass shift explains a measurable change in Earth’s rotation and axis. Flares light up the outer atmosphere; they do not re-aim the pole. (a) treats both as explanations; (c) drops a true statement; (d) drops both.
Same topic · past papers
UPSC has asked this before
These previous-year questions sit on the same topic. Open one to practise the earlier ask.