A fish is at the surface with high water flow and a fish down with a low water flow compare the counter current flow between the fishes

C) to ensure each new cell has an exact copy of the dna

It might. it might because if you think about if they discovered if we came from (lets say something funny like aliens) and thy found cells that matched and they would have t do more research about it but would most probably change their theory.

Is there a photo attached? it may not be loading correctly for me bc of my internet