Theory:

Believe it or not, deserts are not merely the land of sand and dryness but the home of some varieties of plants and animals. It's a common misconception that deserts are devoid of water because some deserts have water in them. Water resources occur in the form of springs and wells in those deserts. This water-available region in deserts is called 'Oasis'. Generally, a desert receives not more than $$25$$ centimetres (10 inches) of precipitation a year, and so rainfall is one of the essential factors that determines the dry condition of the desert.

Water from springs and wells spreads through Oasis, which helps in maintaining its fertility. With the existence of Oasis among deserts, plant, human and animal life is possible.

Nonetheless, some deserts exist without water. As a result, only a few plants can survive in those sandy regions.

While it may be true that a desert ecosystem is not the same as a forest, it has its advantages as forests. Like forests that give out food, paper, woods, oil, minerals, etc., deserts give gold, copper, oil, minerals, sand, etc.

Like the rich forests and oceans, deserts play a vital role in the earth, covering about one-fifth of its surface. Thus, deserts are not useless sand-filled regions as some think but a valuable and essential part of the earth's surface.