Deserts are dry, desolate places where water is extremely rare and

Deserts are dry, desolate places where water is extremely rare and precious. It (1)____ rains, and the rain never lasts long, so the only plants and animals that live in the desert are those that are able to conserve water.
Not many people live in the desert. Those who do live near water. Almost all of the 60 million people in Egypt live (2)______the Nile River. In satellite pictures, the agricultural land hugging the Nile River looks like a green ribbon winding through the dry Sahara Desert.
In some places near the equator, rain falls year-round. The warm temperatures and (3)_____weather result in lush tropical rainforests in Central and South America, Africa and Asia.
There are more species of animals and plants in the rainforests than anywhere else on Earth so many that most have not even been (4)_____. People living in the forests and, more recently, scientists have learned that many of the exotic plants are valuable. Some of them are sources of food and others are sources of important medicines.
In some parts of the world, the rainforests are in danger. (5)____ satellite pictures show rainforest destruction very clearly, they are being used to monitor this huge jungle. Even a rainforest the size of the Amazon can be photographed in only a few hours by a satellite.