nReaders will get an in-depth look at the important systems that make up the human body. Alongside engaging and informative photos, readers will learn about the circulatory, digestive, endocrine, immune, muscular, nervous, reproductive, respiratory, and skeletal systems and how each are critical to a healthy, functioning body. Features include a glossary, additional resources, and an index. Aligned to Common Core Standards and correlated to state standards. Abdo Reference is an imprint of Abdo Publishing, a division of ABDO.