Which best explains why a thick tropical forest filled with large plants typically has a lot of water vapor in the air?

Question

The plants undergo transpiration.
The plants undergo condensation.
The plants prevent water from evaporating.
The plants prevent water from becoming runoff.

Answer 1

The best explanation for why a thick tropical forest filled with large plants typically has a lot of water vapor in the air is:

The plants undergo transpiration.

Transpiration is the process by which plants release water vapor into the air from their leaves. In dense forests, this process occurs on a large scale, contributing significantly to the humidity and water vapor in the atmosphere.