What is a Desert?

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A desert may be defined as an area where the average annual rainfall is less than 250 mm. Deserts cover between one eighth and one seventh of the Earth's land surface. Hot deserts lie between 200 and 300 on either side of the equator. The very word desert paints the picture of a vast sandy and scorching hot area with only dunes and sand dunes. But a desert need not be hot. There are cold deserts too that remain covered with snow and ice. Cold deserts cover one sixth of the world's surface. Antarctica is a cold desert. The biggest hot desert is Sahara in Africa.

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