A coral reef is made up of three main components:
A hard surface
Submerged rocks or other hard surfaces provide a place for corals to attach and serve as habitat for many coral reef animals.
Coral polyps are tiny little animals that are related to anemones and jellyfish. They can live individually, or in large colonies that comprise a coral reef.
Between 1 and 8 million species are associated with coral reef ecosystems, and many play crucial roles in maintaining a healthy, functioning, and balanced reef.