Answer:
1
Step-by-step explanation:
Cool air is denser (heavier) than warm air. During a hot day, when the air mass in a region is heat by the sun, it warms up and picks up more moisture. The warm moist air rise as it is pushed up by the denser air mass coming from the adjacent cooler regions. As the warm air rises, it cools with altitude and the moisture in it condenses to clouds that later precipitate as rain.