Lungs do not collapse between breaths and some air always remains in the lungs which can never be expelled because
1. there is a negative pressure in the lungs
2. there is a negative intrapleural pressure pulling at the lung walls
3. there is a positive intrapleural pressure
4. pressure in the lungs is higher than the atmospheric pressure

Options

A. there is a negative pressure in the lungs
B. there is a negative intrapleural presure pulling at the lung walls
C. there is a positive intrapleural pressure
D. pressure in the lungs is higher than the atmospheric pressure

Answer

B