Genetic mutations are passed on because when the DNA is mutated, it stays that way. Therefor the mutated DNA would continue to be passed on because the same DNA is passed on to the offspring during meiosis, which produces gametes (eggs and sperm) mutations and all!
They use anaerobic cellular respiration to produce NAD+ from NADH.
The answer you are looking for is B. Bubbles form when two chemicals are mixed together.
Im pretty sure it would be 2, but sorry if im not much help.