<prompt> Negative intrapleural pressure is due to -Uniform distribution of surfactant over alveoliNegative intraalveolar pressureAbsorption by lymphaticsPresence of cartilage in the upper airway  <response>: The intrapleural pressure becomes more negative at the end of inspiration and less negative at expiration. It ranges between -3 and -6 mmHg. The elasticity of lung and rib cage causes it to recoil and thus creating the negative pressure. The lymphatic drainage of the pleural fluid also creates a negative pressure. 