Which is the best integrated understanding of clouds and precipitation?

Correct answer: Clouds are groups of condensed particles, and precipitation occurs when they become able to fall

Answer: A. Water vapour is invisible. When moist air cools and condensation occurs, tiny liquid droplets or ice crystals form and remain suspended, producing a cloud. A cloud becomes a precipitation source only when some particles grow large or heavy enough to fall. They may grow through collision and coalescence of droplets, or through growth of ice crystals in cold or mixed clouds. The falling particles can still melt or evaporate before reaching the ground. A is correct because it connects condensation, cloud formation, particle growth, and falling precipitation without treating them as the same event. B is wrong because clouds are not rocks and precipitation is not an earthquake. C is wrong because many clouds do not produce heavy rain. D is wrong because water vapour is the starting moisture for cloud formation. Memory cue: “Vapour condenses, particles grow, then precipitation may fall.”