What other research could be done to gather more information about Earth's interior?

The study of seismic waves is known as seismology. Seismologists use seismic waves to learn about earthquakes and also to learn about the Earth's interior. One ingenious way scientists learn about Earth's interior is by looking at earthquake waves.

answer; john stuart mill's principle of utility is your answer; /// good luck

the correct answer on edgen is:

(c.) prevent the spread of communism.

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