Which two of the following changes (A-B) usually tend to occur in the plain dwellers when they move to high altitudes (3500 m or more )
(A) Increase in red blood cell size
(B) Increase in red blood cell production
( C) Increased breathing rate
(D) Increase in thrombocyte count
A. (A) and (B)
B. (B) and (C )
C. (C ) and (D)
D. (A) and (D)
