Question

People who have migrated from the planes to an area adjoining Rohtang pass about six months back.
A) Suffer from altitude sickness with symptoms like nausea, fatigue, etc.
B) Have the usual RBC count but their hemoglobin has high binding affinity to oxygen,
C) Have more RBCs and their hemoglobin has a low binding affinity to oxygen.
D) Are not physically fit to play games like football.

Answer 1

Hint:Atmospheric pressure is inversely proportional to altitude. As the altitude increases, the pressure of air decreases because there are less air molecules at higher elevation.

Complete answer:
Let us analyse the options to find the correct answer.
>Option A: People who have migrated from planes to the area adjoining Rohtang pass will suffer from exhaustion, nausea and fatigue for 1-3 days, But after some time they become acclimatized. Hence, this is an incorrect option.
>Option B: At higher altitudes RBC count is increased by hormone erythropoietin to increase the delivery of oxygen to muscles. Hence, this is an incorrect option.
>Option C: RBC count is increased at higher altitudes but the binding affinity of haemoglobin to oxygen is reduced. This is because at such places air is dense and oxygen levels are low. If the affinity of oxygen to hemoglobin is low it will allow easy release of oxygen to cells. It is an adaptation to beat chronic hypoxia. Hence, this is the correct option.
>Option D. This is an incorrect option as in 6 months time people become acclimatized to the environment in which they live. Physiological changes like increased production of RBCs allow people to do physical activities.

Additional Information:
Polycythemia is an increase in red blood count when a person is living at higher altitudes for a long time.
Chronic hypoxia is a symptom of low blood oxygen.

Thus, the correct answer is Option C) Have more RBCs and their hemoglobin has a low binding affinity to oxygen.

Note: People residing in elevated areas possess a higher count of RBCs. This is because of decreased air pressure which leads to reduced oxygen content in the same volume of air.