What occurs when rising air expands and cools as pressure decreases with altitude?

When air rises, it encounters lower atmospheric pressure, which causes it to expand. As this air expands, it cools due to the adiabatic process, meaning that it loses heat without exchanging energy with its surroundings. This cooling of the rising air can lead to condensation if the air reaches its dew point, where it becomes saturated with moisture. When enough moisture condenses, it forms tiny water droplets, which coalesce to create clouds.

This process illustrates the relationship between temperature and pressure in the atmosphere and highlights how cloud formation is a direct consequence of the expansion and cooling of rising air. The other options, such as precipitation occurring or air stagnating, depend on additional factors and are not the immediate outcome of rising air expanding and cooling. Heating of the air is also not a result of this process, as the cooling is a direct effect of expansion under lower pressure.