Issues 21 offers teachers the resources they need to meet content and literacy needs while making learning provocative and meaningful. Each book features an essential question that provokes an examination of an issue from different perspectives. Students will have opportunities to discover innovative ways of understanding, confronting, and addressing issues they really care about; and to develop 21st century competencies: critical thinking, creativity, communication, collaboration, character, and ethical citizenship. The essential question of this volume asks is how does our lifestyle threaten our health?