).What structure prevents food from entering the trachea?16). What are the two zones of the Respiratory System?17). What is the function of pleural fluid?18). State Dalton’s Law of Partial Pressures.19). What is the percentage of oxygen in atmospheric air versus alveolar air?20). How does carbon dioxide regulate the pH of the body? Health Science Science Nursing MED 110 Share QuestionEmailCopy link Comments (0)