Awoman with normal vision who is a carrier for color-blindness marries a man with normal vision. if this couple has two daughters and a son, what is the probability that none of the three children are color-blind? note: color-blindness is a recessive, x linked trait.

There would be a 100% chance. There would be a 50% chance the children would have normal vision and a 50% chance they would be carriers, but there is no chance that they would actually be color blind. I'm not sure what a recessive, x linked trait is, but this would be the answer if these are normal traits.

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.