Rivers are one of our most important natural resources. Many of the world's great cities are located on rivers, and almost every country has at least one river flowing through it that plays an important part in the lives of its people.
Sincethe beginning of history, people have used rivers for transportation. Thelongest one in the United States is the Mississippi. The lifeline of Egypt isthe Nile. To the people of India, theGanges is great, but it is also important for transportation; ships can travelalong it for a thousand miles. Other great rivers are the Congo in Africa andthe Mekong in Southeast Asia. The greatest of all for navigation, however, isthe Amazon in Brazil. It is so wide and so deep that large ships can go abouttwo thousand miles upon it.
Besides transportation, rivers give food, water to drink, water for crops, and chances for fun for the people who live along their banks. In order to increase the supply of water for crops, engineers sometimes build a dam across a river and let a lake form behind the dam. Then people can use the water not only to grow crops but also to make electricity for their homes and industries.
However, large cities and industries located upon rivers often make problems. As the cities grow in size and industries increase in number, the water in the rivers becomes polluted with chemicals and other materials. People are learning the importance. However, if they want to enjoy the benefits of this natural resource, they must do more.
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