<prompt> Hemoglobin unlike myoglobin showsa Sigmoid curve of oxygen dissociationb Positive cooperativityc Hills coefficient of oned None of aboveacabadbc  <response>: Hb-O2 dissociation curve- Sigmoid shapeCo-operativity- Hb is a tetramer. If one molecule of O2 binds to the tetramer more easily if other O2 is already bound. Hills coefficient of Hb- 2.8 