Inspiration Normally Takes Place When the Intrathoracic Pressure Is Slightly

Inspiration normally takes place when the intrathoracic pressure is slightly below atmospheric pressure and when a partial vacuum exists between the parietal and visceral pleural (intrathoracic) surfaces.As the muscles of inspiration contract to enlarge the chest cage,what action by the lungs occurs to facilitate air intake?

A) The lungs recoil and expand to draw air into them.
B) The lungs are passive and follow the diaphragm and chest wall.
C) The lungs produce a pressure gradient that suctions air.
D) The alveolar sacs expand when triggered by neural triggers in all 10 lung segments.