Which statement is correct regarding internal and external respiration?

• A. Internal respiration takes place in the alveoli of the lungs.
• B. External respiration occurs within the mitochondria of cells.
• C. Internal respiration involves the exchange of gases between the blood and the body's cells.
• D. External respiration is the process of oxygen being used by cells to produce energy.

Answer: (C)

Verified step by step guidance

1. Understand the definitions: Internal respiration refers to the exchange of gases between the blood and the body's cells, while external respiration involves the exchange of gases between the air in the alveoli and the blood in the pulmonary capillaries.
2. Identify the location of each process: Internal respiration occurs at the cellular level throughout the body, whereas external respiration takes place in the lungs.
3. Clarify the processes involved: In internal respiration, oxygen is delivered to the cells and carbon dioxide is picked up from the cells. In external respiration, oxygen is taken into the blood from the alveoli, and carbon dioxide is expelled from the blood into the alveoli.
4. Correct the misconceptions: Internal respiration does not occur in the alveoli; it occurs in the tissues. External respiration does not occur in the mitochondria; it occurs in the lungs.
5. Summarize the correct statements: Internal respiration involves the exchange of gases between the blood and the body's cells, and external respiration involves the exchange of gases between the alveoli and the blood.