Q. Assertion : Inspiration occurs when there is a negative pressure in the lungs with respect to the atmospheric pressure.
Reason : During inspiration, a decrease in pulmonary volume increases the intra-pulmonary pressure than atmospheric pressure which forces the air from outside to move into the lungs.

 2219  229 Breathing and Exchange of Gases Report Error

Solution:

The movement of air into and out of the lungs is carried out by creating a pressure gradient between the lungs and the atmosphere. Inspiration occurs when the pressure within the lungs (intra-pulmonary pressure) is less than the atmospheric pressure, i.e., there is a negative pressure in the lungs with respect to atmospheric pressure.