Q. People living at sea level have around 5 million RBC per cubic millimeter of their blood whereas those living at an altitude of 5400 metres have around 8 million. This is because at high altitude :
A) people get pollution-free air to breathe and more oxygen is available
B) atmospheric O₂ level is less and hence more RBCs are needed to absorb the required amount of O₂ to survive
C) there is more UV radiation which enhances RBC production
D) people eat more nutritive food, therefore more RBCs are formed
Explanation
[Solution from source] At high altitude the partial pressure of oxygen is low, so the body makes more RBCs to carry enough oxygen to the tissues. The air there actually has less available oxygen, not more. Answer (2).
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.