What happens to the respiratory process in a man going up a hill?

Explanation

### Step-by-Step Solution:

1. **Understanding Altitude Effects**: As a person ascends a hill, the altitude increases. This change in altitude affects the atmospheric pressure and the availability of oxygen.

2. **Decrease in Oxygen Levels**: At higher altitudes, the concentration of oxygen in the atmosphere decreases. This means that there is less oxygen available for the body to utilize during respiration.

3. **Impact on Oxygen Supply**: With less oxygen available, the body experiences a deficiency in oxygen. This deficiency can lead to lower levels of oxygen in the blood, which is critical for various bodily functions.

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