Question: a why does fetal hemoglobin have a higher affinity for...

A. Why does fetal hemoglobin have a higher affinity for O₂ than adult hemoglobin?

B. Residues H2, K82, and H143 of both b1 and b2 in adult hemoglobin play a role in 2,3-bisphosphoglycerate binding. What are the corresponding residues in fetal hemoglobin?

C. What does this do to the binding site in fetal hemoglobin?

---Download the PyMOL file 1FDH to investigate this difference. (The picture above is the downloaded picture. Please help me out with this question. Please explain them in detail. )