If an owl eats a mouse that eats grass, the owl is a
A. Producer
B. Second- level consumer
C. First level consumer
D. Decomposer

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.