- A A fall in carbon dioxide levels within the blood
- B Hypoxia, which raises erythropoietin secretion from the kidney
- C Increased atmospheric pressure acting directly on bone marrow
- D Faster hemoglobin breakdown occurring in the spleen
Correct answer: B. Hypoxia, which raises erythropoietin secretion from the kidney
Explanation: Low oxygen levels (hypoxia) at high altitude stimulate the kidneys to secrete more erythropoietin, which increases red blood cell production to improve oxygen-carrying capacity.
Concept context
The mechanics of breathing, lung volumes, gas transport in blood, the Bohr effect, and respiratory regulation.