If a gene sequence in one strand of dna reads accgttcga, then when the dna is unwound and replicated, the newly created strand opposite of this will read

bc blah

explanation:

bc blah

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.