Why does warm air rise over cold air in cyclonic rainfall?

Correct answer: Because warm air is less dense

Answer: A. Heating makes air expand, so the same mass occupies more space and becomes less dense than surrounding colder air. At a boundary between air masses, the denser cold air tends to remain lower and can wedge beneath the warmer air. The warm air is therefore lifted over it. As the warm moist air rises, it expands and cools; cooling can lead to condensation, cloud formation and precipitation. B is wrong because air does not become stone when heated. C is wrong because cold air does not always disappear; it remains an important air mass and often helps force the warm air upward. D is wrong because water vapour supplies moisture for cloud and rain formation, although density contrast is the main reason for the lifting described. Memory cue: warm air is buoyant, cold air wedges underneath.