Question

Where on the ocean floor will you find the greatest amount of living organisms?

Answer: the coral reefs
The greatest amount of living organisms can be found in the photic zone where sunlight can penetrate water, and where organisms that photosynthesize depend on sunlight. These photosynthetic organisms supply almost all the energy and nutrients to the rest of the marine food web.

Answer 1

That is not bad, however, I would add the word "live" to just before coral reefs. Dead corals indicate a real problem going on there.