Answer to Question 1
As surfaces, such as twigs, leaves, and blades of grass) cool below dew point, water vapor begins to condense upon them, forming tiny visible specks of water called dew. If the air temperature should drop to freezing or below, the dew will freeze becoming tiny beads of ice called frozen dew. Visible white frost forms on cold, clear, calm mornings when the dew point temperature (the temperature to which air must be cooled in order for saturation to occur) is at or below freezing. When the air temperature cools to the dew point and further cooling occurs, water vapor can change directly to ice without becoming a liquid first. The delicate, white crystals of ice that form in this manner are called frost.
Answer to Question 2
When moist air is warmed, actual vapor pressure will remain constant, saturation vapor pressure will increase, and relative humidity will decrease.