The body needs to defend itself from invaders such as viruses and bacteria. This title explores how cells in the body identify and attack these invaders to keep the body healthy. 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.