Ethanol is an example of a biofuel. it is made from

a.
corn plants

b.
solar energy

c.
phosphorus cycling

d.
radiant energy and geothermal energy

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.

the answer is c on e2020, bud.