Multiple Choice
A cross section of Earth reveals a layered structure that has different thicknesses and densities. How do geologists know this?
A) From drilling and digging down into the various layers.
B) From observing the characteristics of lava and gas issuing from volcanic vents.
C) From observing the transit times through the Earth of waves generated by large earthquakes.
D) From comparisons with drill cores taken by robot spacecraft on Mars and Venus.
Correct Answer:

Verified
Correct Answer:
Verified
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