The Reason for Fetal Globin Chain Switching Is That

Multiple Choice

The reason for fetal globin chain switching is that

A) a fetus does not need oxygen but a newborn does.
B) a fetus has four alpha globin chains and a newborn has four beta globin chains.
C) a fetus' blood is clear until the sixth month, and then globin chains turn it red.
D) the newborn needs more iron than the fetus or embryo.
E) the embryo and fetus receive different concentrations of oxygen compared to after birth.