A saturated solution of a gas in a liquid (in a closed system) is at equilibrium with a fixed number of gas molecules leaving and entering the solution every second. If the gas pressure is increased by compressing the system, the gas volume will , thus disturbing the system. This causes gas molecules to dissolve in order to reestablish equilibrium. A gas is therefore soluble at higher pressures.

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.

that's what i got you can count the number of atoms