Investigating Body Systems introduces readers to the main organ systems of the human body. The science that makes each system function is clearly explained, and new research on the body's processes are explored. Fact-check boxes help separate fact from fiction, and key figures in the development of the scientific method are identified. Investigating the Respiratory System Every Living thing needs to breathe: plants, microbes, and animals-including humans. In fact, the average person takes 17,000 breaths per day. This fascinating book examines the mechanisms that make breathing work and the diseases that make breathing difficult. Full-color illustrations help readers visualize the respiratory system at work.