A species of fish known as Astyanax mexicanus lives in deep underground caves off the coast of Mexico. It is virtually blind. The same fish lives near the surface and has fully functioning eyes. Over time, what will most likely happen to the sighted and blind types of Astyanax mexicanus?
One type will become extinct.
They will become separate species.
They will interbreed and exhibit only the dominant trait.
One type will mutate to become more like the other.