If the Thoracic Wall Is Punctured,air Leaking in Will Cause

Multiple Choice

If the thoracic wall is punctured,air leaking in will cause the lung to collapse.Thus one can conclude that in the normal intact thoracic cavity,

A) lung expansion is passive.
B) air pressure is the same as it is on the outside.
C) air pressure is lower than it is on the outside,which helps keep the lungs inflated.
D) breathing movements keep the lungs inflated.
E) Both a and b