Stille, Darlene R

Discusses the erosion and pollution of soil, the harmful effects of these processes, and ways of preventing them.

Discusses the benefits of air, and looks at the harmful effects and methods of preventing air pollution.

Chronicles five presidential administrations from Theodore Roosevelt to Calvin Coolidge that profiles their early years, political careers, presidency, and legacy.

Simply describes the functioning of the digestive system and explains the process of digestion.

Text and illuminative color diagrams describe the science of water waves, sound waves, light waves, radio waves, and earthquake waves.

Presents a children's story about clown fish for early readers, and describes what they look like, where they live, how they care for their young, and other interesting facts.

Presents a children's story about Bottlenose Dolphins for early readers, and describes what they look like, where they live, how they communication with one another, how they care for their young, and other interesting facts.

Provides information about matter, explaining what it is, describing the three different kinds of matter, and looking at how it changes from one form to another. Includes fun facts, an activity, and a glossary.

Describes the various parts of the human circulatory system and explains how and why blood is circulated throughout the body.

Provides an introduction to the geography, natural resources, history, government, economy, important sites, daily life, and people of Puerto Rico; and includes tips on visiting the commonwealth; related projects, a time line, a glossary, fast facts, a biographical dictionary, and resources.