People need to breathe to stay alive. This title explores how the lungs pull in air in order to send oxygen into the circulatory system. Easytoread text, vivid images, and helpful back matter give readers a clear look at this subject. Features include a table of contents, infographics, a glossary, additional resources, and an index. Aligned to Common Core Standards and correlated to state standards. Kids Core is an imprint of Abdo Publishing, a division of ABDO.