Question

It has been found that people living in very high mountains have many more red corpuscles in their blood than people living in plains. Which one of the following best accounts for this phenomenon ?
(a) the cold climate stimulates the production of red corpuscles to keep the body warm
(b) people of high mountains breathe more quickly
(c) the low air pressure requires more red corpuscles to supply the body cells with oxygen.
(d) the low air pressure in high mountains speeds up the blood circulation so that more red corpuscles are needed

Answer 1

option ,c
(c) the low air pressure requires more red corpuscles to supply the body cells with oxygen

An elevation of land or air above 1200 mts is considered as high altitude.
As the altitude increases, the atmospheric pressure decreases. Thus reducing the level of oxygen.
People living at higher altitudes are used to the lower density of oxygen molecules in the air. They have higher levels of hemoglobin (red blood cells) in their blood which helps them to take in more oxygen.
In contrast, people living at lower altitudes have lesser hemoglobin concentrations as they experience a higher density of oxygen molecules in the air.