Correct option is A
The correct answer is (a).
In Drosophila embryos, Hox genes are expressed in a specific anterior-to-posterior gradient along the developing body axis. The correct order of expression of the Hox genes along this axis is Antennapedia, followed by Ultrabithorax, and then Abdominal A. These genes play crucial roles in determining the identity of specific body segments during early embryonic development. Antennapedia is expressed in the anterior regions, Ultrabithorax in the middle, and Abdominal A in the posterior regions of the embryo.
Incorrect options-
Option (b) is incorrect because Abdominal A is expressed posteriorly, so it cannot be first in the anterior-to-posterior sequence.
Option (c) is wrong as it places Abdominal A before Ultrabithorax, which contradicts the gene order and expression pattern.
Option (d) is incorrect because Ultrabithorax is more anterior than Abdominal A, so it cannot be expressed after Antennapedia.
