Question

Where in the respiratory system does oxygen, from the air breathed in pass into the blood.

Option 1 : trachea

Option 2 :bronchi

Option 3 : bronchioles

OpOpti 4 : alveoli

Answer 1

The primary function of the respiratory system is to exchange oxygen and carbon dioxide. Inhaled oxygen enters the lungs and reaches the alveoli. Oxygen passes quickly through this air-blood barrier into the blood in the capillaries. Similarly, carbon dioxide passes from the blood into the alveoli and is then exhaled.
Hence the correct answer is option D Alveoli