hypoxia triggers increased ___ secretion?

is it carbon monoxide?
or erythropoietin?

After oxygen diffuses into pulmonary capillaries, it diffuses into ___ and binds with __?

a;interstitial fluid;RBC?
b;interstitial fluid;C02?
c;RBC:hemoglobin?
d;RBC:C02?

1 answer

the second is obviously c.
the first is erythropoietin.