Question

clouds are formed when
o sunlight causes water droplets to evaporate.
o liquid water condenses on grass and windows.
o raindrops freeze into tiny pellets and fall to earth.
o water vapor in the air condenses to form liquid water or ice.

Explanation:

Clouds form when water vapor (gas) in the air cools and condenses (changes to liquid or ice). Evaporation (water turning to vapor) is the opposite of what forms clouds. Liquid water condensing on grass/windows is dew, not cloud formation. Raindrops freezing into pellets is sleet formation, not cloud formation.

Answer:

water vapor in the air condenses to form liquid water or ice.