Question

what does subterranean mean? use roots and affixes as clues. occurring above the horizon just after sunset evaporating into the atmosphere due to heat being or operating under the earths surface existing down in the darkest ocean depths

Explanation:

The prefix "sub -" means under or below, and "terra" refers to earth. So "subterranean" means under the earth's surface.

Answer:

being or operating under the earth's surface