Question

Lungs do not collapse between breaths and some air always remains in the lungs which can never be expelled because ______.   

Options

• pressure in the lungs is higher than the atmospheric pressure.   

• there is negative pressure in the lungs.   

• there is a negative intra-pleural pressure pulling at the lung walls.   

• there is positive intra-pleural pressure.  

Answer 1

Lungs do not collapse between breaths and some air always remains in the lungs which can never be expelled because there is a negative intra-pleural pressure pulling at the lung walls. 

Explanation:

As a result of the negative intra-pleural pressure tugging on the lung walls, air always remains in the lungs after breathing and does not collapse between breaths.