Coral reefs are massive limestone structures, made from skeletons of millions of marine animals called coral polyps. As polyps die, new polyps grow on top and next to the dead ones. Many layers of skeletons from the dead polyps form the limestone structure of a coral reef. Other types of animals and plants also contribute to the structure such as: algae, sponge, and mollusks. They cover only 0.2% of the ocean floor and they are home to a quarter of marine plants and animal species. They live in warm, clear, shallow waters of tropical oceans.
The reefs are home to several species of marine…
