It is not a single reef at all. It is made up of over 2900 individual reefs very close to each other . A coral is a tiny marine polyp. It is the living part of the coral reef. There are many different kinds of corals.
Corals feed mostly on plankton.
Coral grows in warm climates where there is clear salt water and sunlight. They don't like pollution. A coral reef is a natural barrier made of the bodies of living and dead coral. It is normally just below the surface of the water. It is made up of living polyps.