Arelationship in which one organisms benefits while the other is not harmed but does not benefit either is called predation. parasitism. commensalism. mutualism.

commensalism

Explanation:

The association of two organisms wherein one is benefited but the other organism is neither benefited nor harmed is called commensalism.

Example: The intestinal flora of human intestine include commensals that derive their nutrition from the unused food. Here, bacteria are benefited but there is no effect on the human.

it's     c       this is a cell (b) with a nucleus (c) containing dna (a). the dna is organized into chromosomes (d). a section of the chromosome that codes for a trait is called a gene (e).

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.