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Question
It has been found that people living in very high mountains have many more red corpuscles in their blood than people living in plains. Which one of the following best accounts for this phenomenon?
Options
the cold climate stimulates the production of red corpuscles to keep the body warm
people of high mountains breathe more quickly
the low air pressure requires more red corpuscles to supply the body cells with oxygen.
the low air pressure in high mountains speeds up the blood circulation so that more red corpuscles are needed
Solution
the low air pressure requires more red corpuscles to supply the body cells with oxygen.
At high altitude, the atmospheric pressure of oxygen is low. As a result, the number of red blood cells in the body cannot meet the cell's demands for oxygen. Therefore, the body increases its red blood cell count in order to supply more oxygen to the body cells, even with less oxygen in the atmosphere. Hence, people living on very high mountains have more red corpuscles in their blood than those living in plains.
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