External respiration occurs in the ________________ and internal respiration occurs in the ___________________

Options

A. Lungs and blood capillaries
B. Lungs and metabolizing tissues
C. Nasal chamber and trachea
D. Alveoli and blood capillaries

Answer

To answer the question, we need to identify where external respiration and internal respiration occur.

### Step-by-Step Solution:

1. **Define External Respiration**:
- External respiration refers to the process of gas exchange that occurs in the lungs. It involves the intake of oxygen from the atmosphere and the expulsion of carbon dioxide from the blood.

2. **Identify the Location of External Respiration**:
- This gas exchange occurs specifically in the alveoli of the lungs, where oxygen diffuses into the blood and carbon dioxide diffuses out.

3. **Define Internal Respiration**:
- Internal respiration, on the other hand, occurs at the cellular level. It involves the use of oxygen by cells to break down glucose, resulting in the production of energy (ATP) and the release of carbon dioxide.

4. **Identify the Location of Internal Respiration**:
- Internal respiration occurs in the metabolizing tissues of the body, where cells utilize oxygen for energy production.

5. **Final Answer**:
- Therefore, external respiration occurs in the **lungs** and internal respiration occurs in the **metabolizing tissues**.