They are called fringing reefs. They grow directly from shore and form borders along the shoreline.
When a fringing reef continues to grow upward from a volcanic island that has sunk entirely below the sea level, an atoll is formed. Atolls are usually circular or oval in shape, with an open lagoon in the center.
The fringing reef is the most common type of coral reef. They however tend to be very sensitive to human induced pollution in the water and are easily destroyed by such.
The shockwave from an undersea earthquake causes 'ripples' in the ocean which are very large swells. When the bottom of the swell touches land, it must build up higher to maintain it's size. Therefore when it approaches the beach, water is drawn away from the beach to compensate for the ocean depth getting shallower under the tsunami swell. More water is drawn from in front of the swell than behind due to the movement of the swell.
The Great Barrier Reef is the world's largest coral reef system composed of over 2,900 individual reefs and 900 islands stretching for over 2,300 kilometers (1,400 mi) over an area of approximately 344,400 square kilometers (133,000 sq mi).
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What are coral reefs?</h3>
Coral reefs are underwater structures made from calcium carbonate secreted by corals. Coral reefs are colonies of tiny living animals found in marine waters that contain few nutrients. Most coral reefs are built from stony corals, which in turn consist of polyps that cluster in groups.
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Coral Reefs of India:</h3>
India has four coral reef areas: the Gulf of Mannar, Andaman and Nicobar Islands, Lakshadweep Islands, and the Gulf of Kutch. Coral reefs protect humanity from natural calamities. They provide revenue and employment through tourism and recreation.
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Coral Reefs of Australia:</h3>
The reef is located in the Coral Sea, off the coast of Queensland, Australia, and is separated from the shore by a strait that is up to 100 miles wide and 200 feet deep in places. The Great Barrier Reef is the world's largest single structure built by living beings, visible from space.
Learn more about coral reefs here: brainly.com/question/10970167
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