Answer: exchange oxygen and carbon dioxide with blood
Step-by-step explanation:
Each respiratory bronchiolus forks into two to ten alveolar ducts. They are conduits consisting of alveoli. Projecting out of the thin walls of the alveolar ducts and respiratory bronchi are numerous alveoli each with a diameter approximately between 0.2 and 0.5 mm.
It is in the alveoli that the gas exchange takes place. In the pulmonary alveoli, oxygen gas from the air diffuses into the sanitary capillaries and penetrates the red blood cells where it is combined with the hemoglobin, while carbon dioxide (CO2) is released into the air (a process called hematosis).