Respiratory System Warm Ups and Bell Ringers: This set includes printable, editable, and digital respiratory system warm ups and bell ringers for biology and anatomy and physiology. Topics include respiratory system structure, passage of air, lungs, alveoli, gas exchange, hemoglobin, breathing mechanism, and regulation of breathing. These respiratory system warm ups help students review how oxygen enters the body, how carbon dioxide is removed, and how the respiratory system maintains homeostas