1. Coral Reefs - a ridge of rock in the sea formed by the growth and deposit of coral
Great Barrier Reef - A coral reef in the western Pacific, off the coast of Queensland,
Australia. It extends for about 2,000 km (1,250 miles), roughly parallel to the coast, and is
the largest coral reef in the world
Polyp - a solitary or colonial sedentary form of a coelenterate such as a sea anemone,
typically having a columnar body with the mouth uppermost surrounded by a ring of
tentacles. In some species, polyps are a phase in the life cycle that alternates with a
medusoid phase