Medications that block the reuptake of serotonin will thereby increase the concentration of serotonin molecules in the select one: a. axon terminals.

The answer is Synaptic gaps

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.