Question

Rain cannot occur until ____?

A. the air becomes saturated with water vapor
B. the water vapor exceeds an absolute humidity of 80 ppm
C. a warm front meets a cold front
D. clouds reach an altitude of 1000 ft

Answer 1

A. The air becomes saturated with water vapor

Step-by-step explanation:

Condensation happens one of two ways: Either the air is cooled to its dew point or it becomes so saturated with water vapor that it cannot hold any more water. Dew point is the temperature at which condensation happens.

Answer 2

A. the air becomes saturated with water vapor

Step-by-step explanation:

The saturated water vapor air forms clouds ( nimbus clouds ) which hold that vapour at a low pressure