Certain species of blind fish living in perpetual darkness in the ocean depths have evolved from ancestors that could see. Research indicates that the brain centers for vision in these fish is degenerating, whereas the brain centers controlling other senses are enlarging. What might be the MOST probable reason for the loss of vision in these fish

Explanation:

Evolution for lack of light. If there is no reason for it you lose the ability but it strengthens other senses. It's compensation. The need to tell if the temperature has increased because of something nearby or ability to feel miniscule movement will increase to compensate for that lack of sense.

the reason the two sea urchins don't compete with each other for food, resources, etc. is because the urchins have adapted to the environment but they have also adapted to each other. this is most likely because the genes of the sea urchins.

a=c and then d= c because of the band so you get ac/dc and you add them together you get sound waves