The basic body structure of the fly in the figure above is determined by a cluster of:

a. repressor genes.
b. hox genes.
c. polypeptides.
d. frameshift mutations.

Ans. B. Hox genes.

Hox genes (homeobox genes) can be defined as a group of related genes, which specify regions of an body plan of an organism's embryo along its head-tail axis. Given figure represents body plan in fruit fly, in which has eight Hox genes, clustered into two complexes.

These genes include labial (for head involution),  proboscipedia (for labial abd maxillary pulps), deformed (maxillary and mandibular segments), sex combs reduced (for cephalic and thoracic development), antennapedia (pair of legs and wings), ultrabithorax (pair of legs halteres), abdominal-A and abdominal-B (for abdomen).

Thus, the correct answer is option (B).

the relative standard reduction potential of the half-cell in which reduction occurs; more positive than the other half-cell. reduction is a chemical process in which electrons are added to an atom or an ion; it always occurs accompanied by oxidation of the reducing agent.