The nurse observes a patient breathing through an open mouth. Which of the follo

3 -- The nasal hairs filter the air as it enters the nares. The rest of the cavity is lined with mucous membranes that contain olfactory neurons and goblet cells that secrete thick mucus. The mucus not only traps dust and bacteria but also contains lysozyme, an enzyme that destroys bacteria as they enter the nose. As mucus and debris accumulate, mucosal ciliated cells move it toward the pharynx, where it is swallowed. The mucosa is highly vascular, warming air that moves across its surface. Cooling of the air would not be happening with nasal breathing. The air would not be neutralized or separated with nasal breathing, so it is not being bypassed with mouth breathing.