It is all of them. To be alive we all kind of have to have a face or body, we all need cells to help us with our day to day activities and we all need to communicate with other humans so that would be social behavior.
In the open ocean, especially around the surface, one of the main sources of food for fish would be the algae that grow at the surface & photosynthesize with the sun. Without fish to regulate the amount of surface algae, they overgrow and block the sun from the organisms on the coral reef.
Without sun, the reef is not able to sustain themselves & it's down hill from there.
I hope this helps!
Topography is the answer :)