During forced expiration,which muscles actively contract?

The lungs do not collapse during breathing and some air always remains in the lungs which can never be expelled because:

If there is a puncture in the thoracic cavity but not in the lungs,then...

In rabbits,expiration occurs by the:

Select the correct statement.

Select the correct process that occurs during inspiration (inhalation):
$(a)$ Contraction of the diaphragm
$(b)$ Contraction of external intercostal muscles
$(c)$ Decrease in pulmonary volume
$(d)$ Increase in intra-pulmonary pressure