Final answer:
Physiologic dead space increases with pulmonary obstructions.
Step-by-step explanation:
A physiological dead space is a region of lung tissue that is not involved in gas exchange because the tissue is not functioning properly. It could be caused by various factors such as alveolar inflation or pulmonary obstructions. For example, if there is an obstruction in the airways, it will increase resistance and make it harder for air to flow through the airways, resulting in an increase in physiologic dead space.