Question

why blood cells increase in number at higher atitude?​

Answer 1

Answer:

Number of red blood cells per unit volume of blood is likely to be higher in a person living at high altitudes. This is in response to the air being less dense at high altitude and number of red blood cells is needed to trap O2 from rarefied air having lowp O2 (partial pressure of oxygen).

Answer 2

To compensate for the decrease in oxygen, one of the body's hormones, erythropoietin (EPO), triggers the production of more red blood cells to aid in oxygen delivery to the muscles.

Number of red blood cells per unit volume of blood is likely to be higher in a person living at high altitudes. This is in response to the air being less dense at high altitude and number of red blood cells is needed to trap O2 from rarefied air having lowp O2 (partial pressure of oxygen).