Part A During inhalation View Available Hint(s) O the diaphragm relaxes. oxygen molecules move into the lungs, and carbon dioxide molecules move out of the lungs O the volume of the thoracic cavity decreases O the diaphragm and rib muscles contract. air moves up he trachea Submit Part B From which structures do oxygen molecules move from the lungs to the blood? View Available Hint(s) O Trachea Bronchi Alveoli O Bronchioles O Nose Submit