Pitch depends on how fast or slow the object vibrates. True Or False

False

Explanation: Pitch does not depend on how fast or slow an object vibrates.

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.