<prompt> Fetal hemoglobin has a higher affinity for oxygen due toLow affinity for 2, 3 DPGReduced pHIncreased release of carbon dioxideOxygen dissociation curve is shifted to right  <response>: Make it very clear in mind that the higher affinity of fetal hemoglobin for oxygen is due to the low affinity of HbF for 2,3 - DPG not due to decreased 2, 3-DPG concentration. HbF does not combine to 2, 3-DPG as avidly as adult hemoglobin.Fetal hemoglobin is left - shifted because it has a low affinity for DPG. Principles of medical physiologyIt is worth noting that DPG does not combine with fetal hemoglobin. That is perhaps one reason why HbF has a greater affinity for oxygen than adult hemoglobin HbF. Understanding of medical physiologyFetal hemoglobin binds less 2-3 DPG it has consequently a greater affinity for O2. _ Pediatric physiologyAll other textbooks have mentioned the same thing.So, the high affinity of HbF to O2 is due to the low affinity of HbF for 2, 3 DPG and not due to decreased 2, 3-DPG concentration.However, amongst the given options, option a is the best answer here because, although there is no decrease in concentration of 2, 3-DPG, because of low affinity for 2, 3-DPG, HbF behaves as if 2, 3-DPG levels are low.Fetal hemoglobin has considerably less affinity for 2, 3-DPG than does adult hemoglobin. In human blood, the affinity of fetal hemoglobin for 2, 3-DPG is only about 40 that of adult hemoglobin. This makes fetal hemoglobin behave as if 2, 3-DPG levels are low; therefore, the oxygen dissociation curve is shifted to the left. Clinical physiology in childhood 