Definition - What does Coral Reefs mean?
Coral reefs are mounds or ridges that are made up of the hard shells or external skeletons of coral as well as calcium carbonate deposits from various species. Some parts of corals reefs have solidified into limestone. The coral is a tiny soft-bodied creature that groups into colonies. It has a hard, stony external shell or skeleton and is related to jellyfish.
Safeopedia explains Coral Reefs
Coral reefs are important for many reasons. One of the most important reasons is that coral provides shelter or protection for many different species of fish. Without coral these species have nowhere safe to live and reproduce. Reef fish and mollusks feed millions of people annually, so coral reefs are a very precious resource. Coral reefs, like other water inhabitants, are threatened by water pollution.