has a lower affinity for oxygen than that of the adult
its affinity for oxygen is the same as that of an adult
has only 2 protein subunits instead of 4
has a higher affinity for oxygen than that of an adult
Solution
Haemoglobin is the protein that makes red blood corpuscles red and binds easily and reversibly with oxygen. Normal values for haemoglobin are $14-20 \mathrm{~g} / 100 \mathrm{~mL}$ of blood in infants, $13-18 \mathrm{~g} / 100 \mathrm{~mL}$ in adult male and $12-16 \mathrm{~g} / 100 \mathrm{~mL}$ in adult females. Haemoglobin is made up of protein globin bound to the red haem pigment. The globin consists of four polypeptide chains-2 alpha and 2 beta. Foetal haemoglobin does not sickle even in those distined to have sickle cell anaemia, $i e$, haemoglobin of foetus has higher affinity of oxygen than that an adult.