if a man with type O blood marries a woman with type AB blood , what are chances that their first child will have type O blood

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.

not sure if this is what you'r looking for nnew= nold