Question

How does air pressure control expiration?

A decrease in air pressure within the lungs allows air to flow in.
An increase in air pressure within the lungs allows air to flow out.
A decrease in air pressure within the lungs causes them to contract.
An increase in air pressure within the lungs causes them to expand.

Answer 1

I think its D

Answer 2

Exhalation (breathing out) requires the air pressure in the lungs to be increased. Expiration is exhalation.

Answer 3

so b

Answer 4

Yes.