The group includes the important reef builders that inhabit tropical oceans and secrete calcium carbonate to form a hard skeleton.
A coral "group" is a colony of myriad genetically identical polyps.
Corals are marine invertebrates in the class Anthozoa of phylum Cnidaria.
Corals also breed sexually by spawning: polyps of the same species release gametes simultaneously over a period of one to several nights around a full moon.The group then promptly dissolved into an argument over who owed who what on their bets on when Jack and Bitty would get together.Ransom and Holster, who had overheard a phone conversation between Jack and Bitty four days before, dodge the question of how they knew about the relationship and start heavily chirping Bitty about the fines he will now owe.Each polyp is a sac-like animal typically only a few millimeters in diameter and a few centimeters in length.A set of tentacles surround a central mouth opening. Over many generations, the colony thus creates a large skeleton that is characteristic of the species.