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The continents and islands of the Earth are dwarfed by the vastness of its oceans, which cover about 71 percent of the Earth’s surface.

What Are Oceans?

A visitor from space approaching the Earth from above Hawaii in the Pacific Ocean would see a blue planet, because the Pacific covers almost half the world. It is bigger than all the continents put together—a vast expanse of water extending from Alaska to the fringes of Antarctica. In addition to the Pacific, scientists have identified four other deep oceans—the Atlantic Ocean, the Arctic Ocean, the Indian Ocean, and the ice-bound Southern Ocean that surrounds Antarctica. However, these five major oceans of the earth are in reality one large interconnected water body. Many people use the terms “ocean” and “sea” interchange- ably when speaking about the ocean. However, there is a geo- graphical difference between those two terms. Seas are smaller and shallower than oceans, and are usually located where the land and ocean meet. Typically, seas are partially enclosed by land. Most are part of a larger ocean—for example, the

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