Answer:
Part A-One of the variations have eyes as well as some pigmentation on them. They live near the surface of the water. The other variation does not have eyes and are often albinos. I found that these fish live in deep, dark caves.
Part B-Yes. I think that these fish are an example of natural selection. The blind fish live in caves and eyes take up energy that could be used somewhere else in the fish. So, they developed into fish with no eyes, allowing them to function more efficiently.
Part C- As a species, they have genetic diversity because the two populations have separate genes. The two fish types developed different traits because of their separate habitats.
I reworded the other answer since the other was just a copied answer. I hope it's different enough! I know it's probably too late to help you but I wanted to at least be able to help someone else who needs the answer :D