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Which of these is an INDIRECT source of knowledge about the interior?
ARocks cut open in a quarry
BSamples from the mine floor
CA core from a drilled well
DGravity and magnetic surveys
Answer & Solution
Correct answer: D. Gravity and magnetic surveys
1. Direct sources are materials we actually hold: mined and drilled rock.
2. Indirect sources infer the interior from measurements.
3. Gravity anomalies, magnetic surveys, seismic waves and meteors all serve.
_Source: NCERT Class 11 Geography, Ch 3 'Interior of the Earth' (kegy203)_
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