Question

People living at sea level have around 5 million RBC per cubic millimetre of their blood whereas those living at an altitude of 5400 metres have around 8 million. This is because at high altitude.

Answer 1

At high altitudes, the atmospheric O2 level is less and hence, more RBCs are needed to absorb the required amount of O2 to survive. That is why, the people living at sea level have around 5 million RBC/mm3 of their blood whereas those living at an altitude of 5400 meters have around 8 million RBC/mm3 of their blood.