Which evidence scientists understand the physical properties of earth's internal structure?

b) earthquake activity

Options:

a) earth's density

b) earthquake activity

c) volcanic activity

d) atmospheric composition

Explanation:

Earthquake activity : Seismic waves are responsible for the earth trembling during earthquakes. An earthquake occurs as seismic waves travel through the interior of Earth’s surface.  A seismograph measures the characteristics of these waves such as how fast they travel as well as their strength.

By studying these attributes in different places, scientists come to understand the makeup of earth’s internal structure. The type of seismic waves most important to this study are body waves which travel through the earth’s interior .