<prompt> Which of the following protein chain pairs represent fetal hemoglobin?a2b2a2e2a2U2a2d2  <response>: Ans. is c i.e., a2U2 Different hemoglobins depending upon there polypeptide chains are HbA or adult hemoglobin a2b2, HbF or fetal hemoglobin a2g2, HbA2 or minor adult hemoglobin a2d2, Gower-1 zeta 2 epsilon 2, Gower-2 a2e2 Portland z2g2 