Overview6 copies each of all three reading levels, 18 books total. Water is an essential resource for life on Earth. Considering how vital and precious water is, it is almost unbelievable that it can be used so carelessly. Sewage, toxic chemicals, fertilizers, pesticides, oil, metals, and solid trash pollute the water in lakes, streams, and oceans around the world. Water Resources explores the ways in which water on Earth has become polluted--and what people around the globe are doing to solve this problem.