Fog produced by frontal activity is primarily the result of which process?

Fog that forms as a result of frontal activity is primarily due to the process of condensation from cooling air. When a warm, moist air mass meets a colder air mass, the warm air is forced to rise. As this air rises, it cools and its capacity to hold moisture decreases. When the temperature drops to the dew point, the moisture in the air condenses into tiny water droplets, creating fog.

The condensation process is critical in this scenario because it takes place when the cooler air cannot contain the moisture present in the warmer air, leading to the formation of fog. This is different from evaporation, which primarily involves the transition of liquid water into vapor. In the context of frontal activity, it is the cooling of the air as it rises that is responsible for fog, rather than the evaporation of precipitation.