Where is the largest known deposit of coral?

   The Great Barrier Reef, the largest chain of coral reefs in the world, extends more than 1,426 miles (2,295 km) along the northern Queensland coast of Australia. A maze of 2,900 reefs and 618 islands, the Great Barrier Reef is a feeding ground for 1,500 species of fish, 300 species of corals, 4,000 species of mollusks, and 400 species of sponges. The humpback whale and several species of sea turtle breed here.
   Coral is a collective name for a group of ¡nvertebrates that secrete calcium carbonate, forming a protective armor into which the animal can withdraw. Its tentacles emerge to seize prey and then pull the food inside its mouth. Single-celled algae also live inside the coral's skeleton. Coral individuals, called polyps, form colonies that grow as the polyps divide and multiply. Every 3 years sev­eral species reproduce during a mass spawning.