Why is it more humid near the equator than near the poles?
a. The atmosphere is thicker at the poles
b. The atmosphere is thinner at the poles
c. Warm air holds more water vapor than cold air does
d. Cold air hold more water vapor than warm air.

C. Warm air holds more water vapor than cold air does

Explanation:

i'm thinking (a) to keep sand in place; ////////////

explanation: a sand fence or sandbreak, like a snow fence, is used to force windblown, drifting sand to accumulate in a desired place. sand fences are employed to control erosion, sand dune stabilization, keep sand off roadways, and to recruit new material in desert areas.