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Where does the absorption of oxygen from the atmosphere into the blood occur?
Bronchi
Alveoli
Trachea
Capillaries
The correct answer is: Alveoli
The absorption of oxygen from the atmosphere into the blood occurs in the alveoli. These tiny, balloon-like structures are located at the ends of the bronchioles in the lungs and are surrounded by a network of capillaries. The alveoli provide a large surface area for gas exchange, which is crucial for efficient absorption of oxygen. Oxygen from the inhaled air diffuses across the thin walls of the alveoli into the blood present in the capillaries. This process of diffusion occurs because of the difference in partial pressures of oxygen, allowing oxygen to move from an area of higher concentration (in the alveoli) to an area of lower concentration (in the blood). While the bronchi and trachea are important for conducting air into the lungs, they do not participate directly in the gas exchange process. Capillaries, on the other hand, are essential for transporting oxygenated blood throughout the body once the oxygen has been absorbed from the alveoli. However, the actual absorption occurs specifically in the alveoli.