Without bones and muscles, running and jumping wouldn't be possible--and neither would just sitting or standing! The skeletal and muscular systems give the body shape and power. Readers learn these simple facts as well as the details of teeth, tendons, and skin, all of which are part of or work with these body systems. Detailed graphic organizers further explain important biological processes and functions to readers as sidebars add interesting information about freckles, nail health, and more! A colorful layout and many photographs enhance knowledge readers will be able to relate to their own bodies immediately.