Question

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

Explanation:

Air moves from areas of high pressure to areas of low pressure. So, changes in air pressure directly affect the movement of air. The size of the air mass is mainly related to the volume of air, the amount of moisture in air is related to humidity - related processes like evaporation and condensation, and temperature of air is related to heat transfer processes.

Answer:

the movement of air