What does dr. carroll mean when he says, "while mutation is random, natural selection is not"?

the answer is c cumulus. cumulus clouds can be seen on a gray and rainy day, because cumulus clouds create thunderstorms. give me brainliest if right.

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.