Which process occurs when sweat evaporates from the skin?

The process occurring when sweat evaporates from the skin is evaporation. This phenomenon involves the transformation of liquid sweat on the skin surface into water vapor, which can then disperse into the air. Evaporation is a cooling mechanism for the body; as sweat evaporates, heat is absorbed from the skin, leading to a decrease in body temperature.

When we consider the context of the other options, heat exchange refers to the transfer of thermal energy between different objects or the environment, which can occur during the evaporation process but is not specific to it. Conduction involves the transfer of heat through direct contact, which does not apply to the process of sweat evaporating. Condensation, on the other hand, is the process where water vapor turns back into liquid, which is the opposite of what occurs during evaporation. Thus, the key concept here is that evaporation specifically describes the phase change from liquid to vapor, making it the correct answer.