Gene u controls the expression of other genes; gene u is a what gene? recessive modifying dominant haploid regulating diploid

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.

its b. greenhouse gasses trap uv rays for heat so that the plants stay alive.

answer; ///progressive relaxation;