Question

In human pre foetal stage the globulins are
A. One
B. Two
C. Three
D. Four

Answer 1

Hint: The various forms of the current, normal human hemoglobins vary within their tetramer–dimer subunit interface strengths (stabilities) by three orders of magnitude within the liganded (CO or oxy) state. The presence of embryonic subunits winds up in an exceedingly mean 20-fold weakening of tetramer–dimer interfaces compared to corresponding hemoglobins containing adult α-subunits.

Complete answer:
The Hb Portland-1, Hb Gower-1, and Hb Gower-2, are the three common embryonic hemoglobins and are normally present during the first few months of life, and these are studied in some detail (Huehns and Shooter 1965; Brittain 2004). Implantation is the stage of pregnancy in humans, at which the embryo adheres to the wall of the uterus. At this stage of prenatal development, the conceptus is termed a blastocyst. It's by this adhesion that the embryo receives oxygen and nutrients from the mother to be able to grow. This stage has three globulins.
Additional information: Subunit exchange occurs at the amount of the dimer, although tetramer formation reciprocally influences the number of dimers available for exchange. Between the subunit types, the competition has occurred so pairs of weak embryonic hemoglobins can exchange subunits to form stronger fetal and adult hemoglobin.
Hence, option: Three is the correct answer.

Note: The dimer–monomer interfaces of those hemoglobins differ by a minimum of 500-fold within their strengths; such interfaces are weak if they contain subunits and exchange with added $β$-subunits within the design of $β_4$ (HbH) significantly faster than do those with $α$-subunits.