Why does the RBC count rise in people who live at high altitudes?

• A. Due to the high partial pressure of oxygen at high altitudes, more RBCs are required to supply oxygen to the body cells.
• B. Due to the low partial pressure of oxygen at high altitudes, more RBCs are required to supply oxygen to the body cells.
• C. Due to the low partial pressure of oxygen at high altitudes, more RBCs are required as the speed of blood circulation increases.
• D. Due to the high partial pressure of oxygen at high altitudes, more RBCs are required as the speed of blood circulation increases.

Answer: (B)