Biology 9700 · AS & A Level · Transport of oxygen and carbon dioxide

Transport of oxygen and carbon dioxide — practice question

What accurately describes the importance of the rise in the red blood cell count of humans who move from living at low altitude to high altitude?

  • AAfter a few weeks at high altitude, the number of red blood cells increases to compensate for the lower availability of oxygen in the air.
  • BAt high altitude, the bone marrow produces more red blood cells to provide binding sites for the increased number of oxygen molecules available.
  • CAt high concentrations of oxygen in the blood, a cytokine stimulates the production of red blood cells to increase the oxygen-carrying capacity of the blood.
  • DAfter only a few days at high altitude the number of red blood cells increases considerably to compensate for the lower availability of oxygen in the air.

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