A. The dew will absorb all the heat
B. Saturation vapor pressures always increase at night
C. At saturation, latent heat of condensation is released into the air
D. Both (b) and (c)
If the dewpoint happens to be much lower than the temperature, the air will cool off much more rapidly at night than if the dewpoint was closer to the temperature in the evening. This is why dry regions such as the high plains and desert regions have such large differences between the high and low temperature.
Moist areas, such as regions near the coast tend to have a smaller spread between the high and low temperature. If the air has a high moisture content, some longwave radiation emitted by the earth’s surface will be radiated back toward the surface.