What are coral and coral reefs?

animal-kingdom
cbse

#1

Corals are minute conidarians, which secrete deposites of lime and calcium carbonate.
Coral reefs: In many coral species, new living corals develop over the old dead corals giving rise to coral reefs and island. The reef builing corals require warm shallow waters. The coral reefs provide a comfortable living place for a variety of animal species. They form stable marine ecosystems.