Question

select all that apply
the number of red blood cells can increase following _.
□ strenuous exercise
□ an increase in altitude
□ an increase in water consumption
□ decrease in altitude
□ a bone marrow failure

Explanation:

Strenuous exercise can cause the body to need more oxygen - carrying red blood cells, so their number can increase. An increase in altitude leads to lower oxygen levels, prompting the body to produce more red blood cells to carry oxygen. An increase in water consumption has no direct impact on red - blood - cell production. A decrease in altitude means more oxygen is available and there is no need for an increase in red blood cells. Bone marrow failure would lead to a decrease in red - blood - cell production rather than an increase.

Answer:

A. strenuous exercise
B. an increase in altitude