I think B is the correct answer. Answer choices C & D are about dolphins, but they do not have anything related to negative effects surrounding human and dolphin interaction. A, on the other hand, may seem like a good choice, but then again, the answer is too vague.
DNA is a chain of nucleotides bonded together. On that chain there are particular portions of it that the sequence of the nucleotide codes for particular proteins; this is known as a gene. In eukaryotric cells, DNA is coiled around proteins such as histones to form chromatids which when two join at the centre by a centromere to form a chromosome.
Answer: Wind
Explanation:
A renewable source of energy won't be artificial or man- made. It's energy that won't run out.