The ocean covers 71 percent of the Earth's surface and contains 97 percent of the planet's water, yet more than 95 percent of the underwater world remains unexplored.  The ocean and lakes play an integral role in many of the Earth's systems including climate and weather.
3.5 million square miles of coastal and deep ocean waters.
hope it will help u mark as the best....
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See the image below for graphical understanding :-)
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