Why does your stomach ache if you eat too much? What makes a cut finger stop bleeding? Basic biology fascinates children, and each book in this kid-friendly collection begins with an engaging narrative to illustrate questions like these. A revealing question-and-answer format follows, explaining the elements that form a system of the human body, such as the digestive, circulatory, or nervous system. Colorfully designed sidebars also spotlight pioneers in medicine and describe common illnesses.