Answer:
A coral reef is a reef-shaped structure in the sea, formed by anemones and which over time becomes large enough to have a significant ecological and physical impact on its environment. These are the largest structures built from living organisms in the world. Coral reefs are complex marine ecosystems. They are a biotope (area of life) of a biocenosis (community of living beings) consisting of plants and animals, for example worms, shellfish, sponges, thorns and crustaceans. Coral reefs play a significant role as “breeding grounds” for the offspring of fish inhabiting the high seas.