A cell membrane is semi-permeable. What does that mean? Select one:
a. It lets things in, but not out of the cell.
b. It let things out, but not into the cell.
c. It Lets certain things in and certain things out of the cell

C

Explanation:

Semi-permeable  means it lets particular things in. It is also called a selectively permeable membrane

answer; i believe the correct answer is (replication is not conservative);

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.