One brain area potentially involved in obsessive-compulsive disorder is the:

this protocol provides a detailed procedure for agarose-based ip to purify and enrich the protein of interest.

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.