Final answer:
Air masses primarily form in low-pressure zones, where moist air rises and condenses, producing clouds.
Step-by-step explanation:
Air masses do primarily form in low-pressure zones. Low-pressure systems occur when the Earth's surface atmospheric pressure is lower than the surrounding environment. In these low-pressure zones, moist air rises and condenses, producing clouds. This movement of moisture and air within weather fronts is what instigates most weather events.