General Knowledge - Basic General Knowledge - Discussion

Coral reefs are underwater structures made from calcium carbonate secreted by corals. Corals are colonies of tiny living animals found in marine waters containing few nutrients. Most coral reefs are built from stony corals, and are formed by polyps that live together in groups. The polyps secrete a hard carbonate exoskeleton which provides support and protection for the body of each polyp. Reefs grow best in warm, shallow, clear, sunny and agitated waters.

Coral reef are aragonite sturcture produce by living animal colonies, found in marine water containing few nutrients. In most healthy reefs, stony corals are predominant.

Rainforest of the ocean.

What does it mean?