Karen is studying an area that has many trees and goes through all four seasons. The trees lose their leaves as the seasons progress. Which biome is she studying?

deciduous forest
grassland
desert
tropical rain forest

Deciduous forest

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.

i believe it is "they are not used up by reactions" as the answer to your question, text me back if this is correct because i just learned this.