Physiology Residual volume of lung is defined as: March 2013 A Additional volume of air that can be inspired forcefully after the end of normal inspiration B Volume of air breathed out of lungs in a single normal quiet respiration C Additional volume of air that can be expired forcefully after normal expiration D Volume of air remaining in lungs even after forced expiration 💡 Explanation Residual volume of lung is defined as: March 2013 ✓ Correct Answer: D. Volume of air remaining in lungs even after forced expiration