question_answer

Which two of the following changes (a - d) usually tend to occur in the plain dwellers when they move to high altitudes (3,500 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

Changes occurring are:

A)  [b] and [c]                    

B)  [c] and [d]

C)  [a] and [d]                   

D)  [a] and [b]