Why does rising air generally cool?

Correct answer: Because it expands as pressure decreases upward

Direct answer: C, because rising air expands as pressure decreases upward. Atmospheric pressure is greater near the surface and generally becomes lower with height. An air parcel that rises moves into this lower-pressure environment. It expands because the surrounding pressure is reduced. Expansion requires energy, and the parcel’s internal energy is used in doing this work, so its temperature falls when there is no major external heat supply. This is called adiabatic cooling. If the air contains enough moisture, cooling may bring it to saturation; water vapour then condenses and clouds can form. A is meaningless and does not describe a physical process. B is wrong because air does not turn into soil. D is wrong because rising air moves upward, not because it falls into the sea. The cooling is not simply because height is cold; the pressure decrease and expansion are the key steps. Memory cue: rising air expands and cools; sinking air compresses and warms.