Final answer:
HbA₂ is composed of two α and two Δ chains and is found in some human beings. HbA is found in normal adult human beings and contains 2α and 2ß chains. HbF is found in growing fetuses and contains 2α and 2γ chains.
Step-by-step explanation:
Hemoglobin (Hb) is a large molecule composed of four folded chains of proteins and iron. One normal type of hemoglobin is HbA₂ which is composed of two α and two Δ chains, also written as α₂Δ₂. HbA₂ is found in some human beings and is considered normal. It is different from HbA, which is found in normal adult human beings and contains 2α and 2ß chains, and HbF, which is found in growing fetuses and contains 2α and 2γ chains.