You are presented with the quiz "Animals with _ form large colonies in shallow tropical water" But you don't know the answer, so you turn to your teacher to ask for hints. He says that "corals form large colonies in shallow tropical water" and "coral is the calcite shell of the coral animal". So, what's the best answer to the question?

Options: A. calcite shells B. an organism's body C. Absorb light D. biological diversity E. Leptospirosis F. produce offspring G. allow growth H. to stay warm
The answer is:
A.