Notes

32 p. : col. ill. How have humans changed the planet? -- What causes air pollution? -- How does air pollution affect climate? -- What other problems does air pollution cause? -- Does land pollution affect lakes and streams? -- Are the oceans polluted? -- What do we do with fresh water? -- How does pollution affect animals and plants? -- What are we doing about pollution? -- What more can we do? -- Can we clean up polluted areas? -- Can we protect wild habitats? -- Does pollution just affect individual species?