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DesertIn physical geography, a desert is a landscape form or region that receives little precipitation. As a consequence, deserts have a reputation for supporting very little life. Compared to wetter regions this may be true, although upon closer examination, deserts often harbor a wealth of life that usually remains hidden (especially during the daylight) to preserve moisture.
Desert landscapes have certain common features. Desert soil is often composed mostly of sand and sand dunes may be present. Exposures of rocky terrain are typical, and reflect minimal soil development and sparseness of vegetation. Bottom lands may be salt-covered flats.
There are different forms of deserts. Some places are deserts even though covered in snow. This remarkable fact comes about because such locations don't receive much precipitation, but what falls remains frozen as snow pack. Non-polar deserts are hot because they have little water. Water tends to have a cooling, or at least a moderating, effect in environments where it is plentiful. In many parts of the world deserts are created by a rain shadow effect in which air masses lose much of their moisture as they move over a mountain range. (Katabatic or Foehn winds)
See also Deserts and Xeric Shrublands.
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