The volume of anatomically dead space air in the lungs of human beings is normally 230 mL, 210 mL, 190 mL, or 150 mL?

The volume of air remaining in the lungs after normal breathing is called the dead space air in the lungs. It is measured by approximately 150 mL in a normal person. It is the volume of the air passing from the nose or mouth to the level of the bronchioles. It is assumed that 30 percent (150 mL) of the tidal volume (500 mL) does not participate in the gas exchange. So, the correct option is D.