What constructs an exoskeleton using calcium carbonate?
animals amoeba sharks insects mammals Man coral bats
A B C D E F G H
Hard corals build by secreting calcium carbonate skeletons.
Corals construct an exoskeleton by secreting calcium  carbonate
What constructs an exoskeleton using calcium carbonate? (A) animals (B) amoeba (C) sharks (D) insects (E) mammals (F) Man (G) coral (H) bats