Large objects that form dense gravity wells in space A. Galaxies B. Star C. Nebulae D. Black holes.​

D. Black Holes

Explanation:

Black holes are large objects that form dense gravity wells in space. Their gravitational pull is so strong that even light cannot escape it. 

a rain shadow is a dry region of land on the side that is protected against the prevailing winds of a mountain range. the prevailing winds are the winds that occur most of the time in a particular place of the earth

prevailing winds carry air toward the mountain range. as the air rises up over a mountain range, the air cools, water vapor condenses, and clouds form. on this side of the mountains, called the windward side, precipitation falls in the form of  rain  or snow. this dry air produces a  rain shadow.