Takes a look inside the human body to understand its most interesting and unusual facts and functions.Leveled by the respected Fountas and Pinnell leveling system, the Extreme Readers series is designed to enhance and nurture your child's reading development. Featuring high-interest topics, this unique nonfiction series offers dramatic photography, graphic illustrations, amazing facts, and a thrilling "extreme facts" list that will engage young readers and keep them turning the pages. Plus, the fact-based books are the perfect supplement for reading and science curricula.