Most of the cells in a human are

Most of the cells in the human body are actually red blood cells.

Explanation:

Adult humans have somewhere around 25 trillion RBCs in their body, on average. Women usually have fewer RBCs than men, while people living at higher altitudes will usually have more.Hope it helps:)

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.

after receiving a stimus, the sensory receptors send(s) signals to the appropriate area of the body.  

the must be sensory neurons.  

hope its .