27.① Coral is an animal, a marine polyp that lives in vast colonies.② Coral reefs are found in tropical waters, between latitudes 30 degrees north and south, inthe Western Atlantic, Indian, and Pacific Oceans.③ Reefs are outcroppings that rise up from the sea floor.④ While most of the reefs are the remains of dead coral, there must be good percentage ofliving coral to ensure that the reef will continue to survive.⑤ The calcium-based skeletons that they secrete build up over time to form vast reefs.
(A) ①③②④⑤
(B) ①⑤③②④
(C) ①②④③⑤
(D) ①②③④⑤