Question

Air moves into the lungs because

• A. the thorax is muscular
• B. contraction of the diaphragm decreases the volume of the pleural cavity
• C. the volume of the lungs decreases with inspiration
• D. the gas pressure in the lungs becomes lower than the outside pressure as the diaphragm contracts

Answer 1

The correct option is D the gas pressure in the lungs becomes lower than the outside pressure as the diaphragm contracts

Air moves into the lungs because the gas pressure in the lungs becomes lower than the outside pressure as the diaphragm contracts. Since the gases move from a region of high pressure to low pressure, the gases/air from outside move into our lungs.