Answer:
It helps cells make proteins.
It provides a source of water
It provides form of usable Nitrogen.
It removes carbon dioxide from the atmosphere.
It destroys harmful bacteria.
First eliminate choices C and D since they both mention that fact 1 is crossing over ( which is also referred to as genetic recombination) . So you're left with A and B and the correct answer is B .
its a stimuli a memory is something you can choose to remember or to do