Which glial cell is found wrapped around nerve fibers in the pns?

Schwann cells

Explanation:

The Schwann cell is a type of glial cell that envelops the axon of neurons in the peripheral nervous system (PNS). Each axon is surrounded along its path by many of these glial cells to form the myelin sheath arround pns axons. One of the main tasks of this type of cells is to act as a support and guide in the processes of regeneration of the peripheral nervous system.

. fibrinogen is soluble in water and is found in high concentrations in the blood, where it waits until needed to form a clot

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.