Question

what happens to air as it rises to higher elevations?
it sinks back down
it cools and expands
it gets warmer and expands
it becomes wetter

Explanation:

As air rises to higher elevations, the pressure decreases. According to the ideal - gas law, with decreasing pressure, the air expands. Also, as it rises, it moves away from the heat - source (the Earth's surface) and cools.

Answer:

It cools and expands