Answer:
Corals belong to the phylum Cnidaria and class Anthozoa. They are marine invertebrates. They live in colonies and excrete calcium carbonate which forms a hard exoskeleton. Thus over many generations, the colony creates a large exoskeleton.
Each coral group is a colony of identical polyps. A polyp is a cylindrical animal with sac like structure. It is around few centimeters in length and few millimeters in diameter. The mouth opening is surrounded by a set of tentacles. It obtains nutrition by eating photosynthetic unicellular dinoflagellates. Â Sometimes it can also catch small fish and plankton by using stinging cells present on tentacles. It can produce both asexually and sexually.
