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. Easy-to-read 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.