The document discusses the Earth's major bodies of water. It notes that there are four oceans - Pacific, Atlantic, Indian, and Arctic - with the Pacific being the largest and deepest. A fifth ocean, the Southern Ocean, was delimited in 2000. It also describes coral reefs, noting that they form in shallow, warm seas from coral polyps' skeletons and grow over old skeletons as the polyps remain fixed in the same spot. Finally, it outlines the three ocean zones defined by sunlight levels and the types of life found in each.
