Geologists obtain indirect evidence about Earth’s interior by a.
measuring pressure differences at Earth’s surface.
b.
estimating temperature inside earth.
c.
directly looking under the many layers.
d.
recording and studying seismic waves.

I'm sure it's D.

Explanation:

They obtain evidences by recording and studying seismic waves.

we can conclude that the melting point of table salt is above room temperature (it's actually 801 deg c). the melting point of mercury must be below room temperature (- 39 deg c).

2b2t

explanation:

2b2t