Using blood doping to artificially increase the number of red blood cells in an athlete might lead to a long term shortage of red blood cells because 1) red blood cells could stop being produced by meiosis2) homeostasis could be disrupted in the athlete3) red blood cells could attack and destroy the extra red blood cells 4) the athlete would no longer need red blood cells

Homeostasis could be disrupted in the athlete

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.

yes? sounds right, but you didn’t ask a question.