Which of the following is the dominant reaction as blood flows through the pulmonary capillaries? (Hb=hemoglobin)
A. H2CO3 --> H+ + HCO3
B. H2O + CO2 --> H2CO3
C. Hb + 4CO2 --> Hb (CO2)4
D. Hb(O2)4 --> Hb + 4O2
E. Hb + 4O2 --> Hb(O2)4
Answer: E. Hb + 4O2 --> Hb(O2)4