The answer is coral Z. This is because it thrives in the
least maximum depth. Shallow coral is vulnerable to changes in the sea surface temperatures that is caused a
phenomenon called coral bleaching. Coral bleaching
is the expulsion of zooxanthellae
by coral-polyp from their symbiotic relationship. This causes the eventual death of
the coral. The temperatures in oceans vary with
depth since the sun rays can only penetrate to a certain depth (this is why it gets colder with the depth of the
ocean).
