Water vapor condensing in clouds causes rain.
If it's raining and barometer is steady, then predict rain.
Water vapor can be detected by barometer. .
How can water vapor be detected?
Options:
[A] Thermometer
[B] radiography
[C] A computer
[D] satellites
[E] Barometer
[F] Evaporation
[G] Windmills
[H] Solar panels