Internet Resources help you find websites that extend learning. Math Connections give more information and examples on math used in the chapters. Summary feature provides an additional review tool for you and reinforces key learning objectives. Environmental Concerns notes highlight key items related to sustainability, energy efficiency, and environmental issues. Critical Thinking Questions and Activities develop higher-order thinking skills and extend your learning and help you analyze and apply knowledge. Review Questions allow you to demonstrate knowledge, identification, and comprehension of chapter material.