<prompt> Residual volume of lung is defined as: March 2013Additional volume of air that can be inspired forcefully after the end of normal inspirationVolume of air breathed out of lungs in a single normal quiet respirationAdditional volume of air that can be expired forcefully after normal expirationVolume of air remaining in lungs even after forced expiration  <response>: Ans. D i.e. Volume of air remaining in lungs even after forced expiration 