Biology · PYQ NEET UG 2016(2)

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

1. pressure in the lungs is higher than the atmospheric pressure.
2. there is a negative pressure in the lungs.
3. there is a negative intrapleural pressure pulling at the lung walls.
4. there is a positive intrapleural pressure.