The best-known desert on Earth is probably the Sahara desert in North Africa. Deserts are found in many different continents, and they cover almost 20 percent of the planet's land surface area. 

Deserts receive only a little rainfall, but they are not completely waterless. Water can be found in deserts in the form of oases, which have formed as a result of underground water concentrations.

Desert plants have developed different strategies for conserving and storing water. For example, species of cacti store water by using their stems, leaves and roots. It is also possible for plants to slow down the evaporation of water, for example with hairy stems that gather moisture. 

The living conditions of the desert are also difficult for animals. The most common desert-dwelling animals are reptiles and rodents. As the days are extremely hot, many desert animals only become active during the night. During sand storms, the animals take shelter in caves and holes in the ground.

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