Why do mountaineers usually suffer from nose bleeding at high altitudes?

Explanation

### Step-by-Step Solution:

1. **Understanding Atmospheric Pressure**:
- At sea level, the atmospheric pressure is higher compared to high altitudes. As you ascend to higher altitudes, the atmospheric pressure decreases.

2. **Effect of Altitude on Blood Vessels**:
- The human body maintains a certain internal pressure in the blood vessels. This internal pressure remains relatively constant regardless of the altitude.

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