Which statements are true about oxygen binding to hemoglobin?
a. T-state is favored when hemoglobin is enriched with Oxygen (all 4 sites bound)
b. R-state is favored when hemoglobin is enriched with Oxygen (all 4 sites bound)
c. Oxygen binding is very robust when O2 concentration in the environment is low
d. Oxygen binding is less robust when O2 concentration in the environment is low
e. A and C
f. B and D