How does exchange of gases occurs at lung surface .

Explanation

### Step-by-Step Solution:

1. **Understanding the Structure**: The exchange of gases occurs at the lung surface, specifically in the alveoli, which are tiny air sacs in the lungs where gas exchange takes place.

2. **Gas Exchange Process**: The primary gases involved in this exchange are oxygen (O2) and carbon dioxide (CO2).

3. **Oxygen Diffusion**:
- Oxygen from the alveolar air diffuses into the blood in the pulmonary arterial capillaries.
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