In the Delta Science Reader Pollution, students read about how human and natural activities can cause land, air, and water pollution. They learn what can be done to reduce pollution and conserve natural resources. They read about the difference between renewable and nonrenewable resources. Noise and light pollution are also introduced. In a biographical sketch, students meet a famous scientist—Rachel Carson—whose warnings about the dangers of pesticides led to the banning of DDT. Finally, students learn about alternative energy sources and why it is important to develop them.