Functional units of lungs are:
Correct answer: A. Alveoli
- A. Alveoli
- B. Bronchioles
- C. Air sacs
- D. Epithelial cells
Explanation
Alveoli: The alveoli are the specialized air-sacs (outpouching) of 200 µm diameter. These are the structural and functional unit of the respiratory system. These are the primary site of exchange of oxygen and carbon dioxide. Tiny air sacs at the end of the bronchioles (tiny branches of air tubes in the lungs). The alveoli are where the lungs and the blood exchange oxygen and carbon dioxide during the process of breathing in and breathing out.
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About Digestion
The human digestive system covers the organs from mouth to anus, the movement of food, and the mechanical and chemical breakdown of carbohydrates, proteins and fats. It also includes the roles of digestive enzymes, bile, absorption through intestinal villi, and the assimilation of nutrients by body cells.
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