2014 · Q113
Which of the following is/are direct source(s) of information about the interior of the earth?
- 1Earthquake wave
- 2Volcano
- 3Gravitational force
- 4Earth magnetism
Select the correct answer using the code given below.
General KnowledgeGeography
- A1 and 2 only
- B2 only
- C3 and 4 only
- D1, 2, 3 and 4
Explanation
The official key treats only volcanoes as a direct source; seismic waves, gravity and magnetism are indirect sources.