In this text, readers can attend to the precise details of explanations and descriptions as expressed in the Reading Standards for Literacy in Science and Technical Subjects. They learn about animal diversity and investigate feeding differences. Animal locomotion, habitats, methods animals use to defend themselves, reproduction, and animal associations and symbioses (such as mutualisms, commensalism, and parasitisms) are explored in depth. This captivating narrative also provides students with informative sidebars to help clarify concepts, including "Closeup" boxes on key topics, "Try This" boxes that encourage students to test experiments, "What Do You Think?" sidebars that pose questions to examine students' reading comprehension, "Applications" boxes that show how biological facts enhance daily life and technology, "Red Herring" sidebars that describe failed biological theories, and "Genetic Perspective" boxes that outline the latest genetic research. The text also includes a biography on Charles Darwin and a timeline.