Step-by-step explanation:
Air parcels can change as they move through the atmosphere due to a variety of factors, including changes in temperature, pressure, and moisture content. These changes can cause the air parcel to expand or contract, which in turn affects its density and buoyancy.
For example, if an air parcel rises and encounters lower pressure, it will expand due to the reduced external pressure and cool adiabatically, meaning without exchanging heat with its surroundings. Alternatively, if an air parcel descends and encounters higher pressure, it will be compressed and warm adiabatically. As the parcel rises or descends, it can also encounter regions with different moisture content, which can cause it to gain or lose water vapor through processes such as condensation or evaporation.
The changes to the air parcel will continue until it reaches a state of equilibrium with its surrounding environment. For example, if the temperature and moisture content of the air parcel become equal to those of the surrounding air, it will stop changing and become part of the larger air mass. However, if the air parcel continues to experience differences in temperature, pressure, or moisture content, it may continue to change as it moves through the atmosphere.