Modern corals are restricted to growing in warm, clear, well-lit, shallow water. Over the last two million years, coral reefs have undergone periods of great growth as well as mass extinctions. All BUT one catastrophic event has contributed to the changes in reefs over the years. That is...

eukarya because is is like alche and b is bacteria and d is animals

explanation:

you can have just about every answer you can think of

your answer is going to be physical weathering

plato users:

d.  

there was a variety of food available on island x, but there were only large seeds and nuts on island y.