Changes in air pressure directly affect which of the following? the movement of air the temperature of air the amount of moisture in the air the size of air mass

The correct answer is - the movement of air.

The air pressure and the changes in it are one of the most influential factors that contribute to the movement of the air masses. Whenever there's air pressures that are bordering each other, but one of them is higher and the other one lower, the air starts to move. The movement always is in the manner from higher towards the lower air pressure. The reason for that kind of movement of the air is because the higher air pressure means that that air is heavier, thus it manages to easily push away, or push upwards, the lower pressure air which is lighter. That is how the wind pasterns on the Earth are formed.