Final answer:
Gas exchange in the lungs happens in the alveoli, which is where oxygen is absorbed into the blood and carbon dioxide is released from the blood to be exhaled.
Step-by-step explanation:
Gas exchange in the lungs occurs in the alveoli, which are tiny air sacs at the end of the bronchial tubes. These alveoli are lined with capillaries, which are small blood vessels. The alveoli are the site where oxygen from the air is transferred to the blood, and carbon dioxide from the blood is expelled into the airways to be breathed out. It's important to note that while goblet cells produce mucus to trap debris and pathogens, and the respiratory bronchioles and larynx are parts of the airway system, they are not where gas exchange takes place.