Which two of the following changes (a-d) usually tend to occur in the plain dwellers when they move to high altitudes (3500 m or more)?
(i) Increase in red blood cell size
(ii) Increase in red blood cell production
(iii) Increased breathing rate
(iv) Increase in thrombocyte count
Changes occurring are:

Options

(a) (ii) and (iii)
(b) (iii) and (iv)
(c) (i) and (iv)
(d) (i) and (ii)

Correct Answer:

(ii) and (iii)

Explanation:

At high altitude, the body undergoes numerous changes in order to increase oxygen delivery to cells and improve the efficiency of oxygen usage. The early changes include increased breathing rate and increased red blood cell production.