If air becomes warm and dry after crossing a mountain which effect is clear?

Correct answer: Rain shadow effect

Direct answer: A, the rain-shadow effect. Moist air commonly rises on the windward side of a mountain, expands and cools, and loses part of its moisture through cloud formation and precipitation. After crossing the crest, the air descends on the leeward side. Descending air is compressed by increasing pressure and becomes warmer; its relative humidity falls, so the leeward side is often drier. This relatively dry area is called a rain shadow. A is correct because it describes the combined result of windward precipitation and leeward warming and drying. B is not the clearest effect described here; convectional thunder is linked to strong vertical heating and instability. C concerns ocean water movement and is unrelated to mountain air. D is generally opposite to the usual leeward effect because warming and drying do not favour snowfall. Memory cue: rise, cool, rain on the windward side; descend, warm, dry in the rain shadow.