What forces air from outside to move into the lungs?

What forces air from outside to move into the lungs?
  1. Decrease in intra-pulmonary pressure
  2. Increase in intra-pulmonary pressure
  3. Increase in atmospheric pressure
  4. Decrease in atmospheric pressure

Solution

The decrease in intra-pulmonary pressure to less than atmospheric pressure forces air from outside to move into the lungs, i.e., inspiration.

Asked in: NCERT

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