Water vapor condensing in clouds causes rain.
Water vapor is a gas in the air.
A gas in the air condensing in clouds causes rain.
What condenses in clouds to cause rain?

(1) evaporation
(2) chlorofluorocarbons
(3) Organic compounds
(4) carbon dioxide
(5) a gas in the air
(6) Chemical energy
(7) peachleaf willow
(8) flooding