2. THE CORAL REEFS A living coral reef is an underwater ridge or mound built of fragments of coral sands and limestone. The Great Barrier-Australia This is the largest coral reef. It it is visible from the space.
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4. RICH UNDERWATER LIFE A lot of species living in the coral reefs; 400 species of corals, 1800 different species of fish,125 of sharks and 5000 of molluscs.
