Q: What forms in shallow tropical water?\nOptions:\n- (A) ocean\n- (B) romance\n- (C) bushes\n- (D) ferns\n- (E) reefs\n- (F) bamboo\n- (G) fossils\n- (H) snorkelling
Let's think step by step below.

User
Corals form large colonies in shallow tropical water. Huge colonies of hard corals form coral reefs . Reefs form in shallow tropical water.
Thus, the answer is (E).
Assistant