Which statement accounts for why the oxygen dissociation curve for haemoglobin has an S-shaped form?
- AAt high oxygen concentrations, oxygen dissociates from the haemoglobin molecule.
- BHaemoglobin becomes saturated at low partial pressures of oxygen.
- COxygenated haemoglobin accepts hydrogen ions from carbonic acid.
- DThe shape of the haemoglobin molecule changes when oxygen binds to it.