Which process describes the transformation of water vapor back into liquid water?

The transformation of water vapor back into liquid water is known as condensation. This process occurs when water vapor cools and loses energy, resulting in the formation of liquid water droplets. For instance, when warm, moist air rises and encounters cooler temperatures, the water vapor condenses, leading to phenomena such as cloud formation or dew on grass in the morning.

In this context, evaporation, infiltration, and transpiration refer to different processes. Evaporation is the conversion of liquid water into water vapor, infiltration is the process where water soaks into the soil, and transpiration is the release of water vapor from plants into the atmosphere. Thus, condensation specifically describes the phase change from vapor to liquid, making it the correct answer.