Final answer:
The statement is false; during expiration, the intra-alveolar pressure actually increases due to the recoil of the lungs as the diaphragm and intercostal muscles relax, causing air to be pushed out.
Step-by-step explanation:
The statement given, "During expiration, the intra-alveolar pressure decreases, causing air to move out of the lungs," is false. During expiration or exhalation, the process is typically passive, involving the relaxation of muscles such as the diaphragm and intercostal muscles. The lung tissue's elasticity causes the lungs to recoil, hence the thoracic cavity and lung volume decrease. This decrease in volume leads to an increase in intra-alveolar or intrapulmonary pressure, resulting in it being higher than the atmospheric pressure. The pressure differential drives air out of the lungs, similar to air rushing out of a balloon when it is let go.