The human body works like a finely tuned machine. The human body has many systems working together and making sure the body works the way that it's supposed to. Through this look at the human body, readers will learn about many of the most important systems in their body and how they keep us moving. Told from the mouth of Snappy the Nile crocodile, readers will discover how their respiratory system keeps them breathing, their digestive system turns food into energy, and more!.