9. Which of the following best describes the term VACUUM?
A. A vibration moving energy from place to place.
B. The part of a wave that is pushed together.
C. Empty Space
D. The material through which a mechanical wave can travel.

C. Empty Space

Explanation:

A vacuum is an empty space.

So, a vacuum is simply an empty space devoid of matter.

the earth would become to overheated and everything alive on it will eventually die from overheating. plants will eventually die as well, water will evaporate, and it will be nothing but a hot planet without anything living on it.