1. which list describes the path oxygen takes to the blood? a. bronchi, alveolar sacs, alveoli, capillaries b. trachea, bronchi, capillaries, alveoli c. larynx, trachea, bronchi, capillaries d. pharynx, larynx, capillaries, alveoli 2. what function do the alveolar sacs serve in the respiratory system? a. cool and clean the air before it moves to the capillaries b. warm and clean the air before it moves to the alveoli c. increase surface area for gas exchange with the capillaries d. decrease pathogens in the air before it moves to the alveoli 3. how does air pressure control expiration? a. a decrease in air pressure within the lungs allows air to flow in. b. an increase in air pressure within the lungs allows air to flow out. c. a decrease in air pressure within the lungs causes them to contract. d. an increase in air pressure within the lungs causes them to expand. 4. what