Sedimentary rock is formed when bonds pieces of clast together. (If using the internet as your answer, at least try to paraphrase it; don't copy and paste it) Fill in the blank. And if you want to, explain why you think it's that answer you've chosen.

Clastic sedimentary rocks are made up of pieces (clasts) of pre-existing rocks. Pieces of rock are loosened by weathering, then transported to some basin or depression where sediment is trapped. If the sediment is buried deeply, it becomes compacted and cemented, forming sedimentary rock.

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 don't know. if i were you, i would search it up online : d