Answer:
a. Relative humidity increases: a decrease in temperature without a change in the amount of water vapor in the atmosphere.
Explanation:
Colder air requires less humidity to saturate compared to warmer air. Therefore, the relative humidity depends on the air temperature. If the temperature drops and the water vapor content remains the same, relative humidity increases. If the temperature increases and the water vapor content remains the same, relative humidity decreases. Additionally, a greater amount of water vapor in the air increases the relative humudity.