Did you know there are 206 bones in an adult's skeleton? Or that the human heart beats about 40 million times every year? In this fascinating series, young researchers will explore the major parts of the human body and learn how they work. Well-organized, easy-to-read text helps readers learn more about their bodies and why they function the way they do. This series explores and supports the standards under "The Human Organism," as required by Benchmarks for Science Literacy: Project 2061.