Question

The atmospheric pressure of oxygen ______ with an increase in altitude.

• A. decreases
• B. increases
• C. remains constant
• D. slightly changes

Answer 1

The correct option is A decreases

Atmospheric pressure decreases with an increase in altitude. As a result, the partial pressure of oxygen will also decrease. Although the percentage of oxygen in inspired air is constant at different altitudes, the fall in atmospheric pressure at higher altitude decreases the partial pressure of inspired oxygen and hence, the driving pressure for gas exchange in the lungs.