Question

How have scientists been able to determine the composition of earth's layers?

A. by looking at how X-rays affect the planet
B. by studying the magnetic fields of various planets and moons
C. by looking at how seismic waves change speeds as they travel through Earth
D. by studying layers of other planets and moons

Answer 1

answer is C. as the seismic waves moves through the earth the slower it gets helps determine the layers or how the waves move differently.