My Science School

Can sand dunes move?

Sand dunes can move slowly, causing deserts to spread over more fertile land. Continuous winds blow the sand to form crescent-shaped dunes. Sand from the top of the dune is blown farther away, and it gradually collects to form a new dune.

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How can people live in extreme climates?

Over millions of years, the human body has altered to suit the climate of the regions we inhabit. In general the hotter the region, the darker the skin of its inhabitants. Also, many people from Asia have a fold of skin in their eyelid to protect them from strong sunlight. People living in hot climates do not need a fat layer to keep warm, so they are usually slim. The Inuits of the Arctic, however, are mostly shorter and stockier to help conserve heat. 

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Which are the wettest places on the Earth?

Tropical rainforests are among the wettest places in the world. In general, most rainfall occurs on the sides of hills and mountains. The wettest place of all is Cherrapunji, in Assam, India. It faces the full force of the monsoon winds that sweep in from the Indian Ocean in July. Their warm, damp air rises in the Himalayan foothills, causing torrential rain. Mount Wai-‘ale-‘ale in Hawaii has the wet days each year. It rains on 350 days on average, and the annual rainfall is the highest recorded anywhere.

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