What happens when the pressure within the pulmonary cavity is higher than the atmospheric pressure?

Additional muscles in the ...... impact the ability of humans to increase the strength of inspiration and expiration. Complete the given $NCERT$ statement with an appropriate option.

Explain the process of inspiration under normal conditions.

Arrange the given steps of expiration in the sequence of events occurring first:
$I.$ Relaxation of the diaphragm and sternum
$II.$ Reduction of the pulmonary volume
$III.$ Expulsion of air from the lungs
$IV.$ Increase in intra-pulmonary pressure
Choose the correct option.

Select the incorrect option for the given diagram (representing inspiration).

The movement of air in and out of the lungs is caused by which of the following?