Answer: evaporation
Step-by-step explanation:
Evaporation fog occurs when surface air is much colder and relatively less saturated than water. Then, when the water evaporates, it inmediately condenses again in small drops of water that stay suspended very close to this body of water.
In other words: This type of fog occurs when cold air moves over warmer water. And it is this difference in temperature that contributes to the formation of fog over the lakes, especially near the polar regions.