Question

What does relative humidity indicate? A. how close air is to saturation B. the amount of heating needed for evaporation C. the ratio of water vapor to carbon dioxide in air D. the amount of water vapor in the air

Answer 1

The ratio of water vapor to carbon dioxide in air.
C

Answer 2

The correct answer is
D. the amount of water vapor in the air

It's not related to carbon dioxide. Water vapor is the amount of water vapor in the air and it is relative because it depends on what the general temperature of the area is. What is considered high humidity in low temperature areas would be considered low humidity in high temperature areas.