The general process whereby nutrients travel from an area of high concentration inside a cell to an area of lower concentration

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.

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answer: collecting information/data

reason: the student is going around and asking people questions to collect data

i hope this