Answer:
Hemoglobin is the pigment present in the red blood cells that helps in the transport of oxygen in the body. A single hemoglobin molecule can binds maximally with four oxygen molecule.
The affinity of the hemoglobin with oxygen depends on the different factors like temperature, presence of the oxygen and the partial pressure. The oxygen affinity for hemoglobin increase with the increase in the oxygen concentration as they shows positive cooperativity. The decline in the oxygen concentration results in decrease in the affinity of hemoglobin with oxygen.