Answer:
Nutritive and varied stimulus exposure divergence
Explanation:
No doubt that Human and Eyes of fly have Pax6 conserved sequences and their primary function is highly conserved.but there is a very simple explanation for their morphological divergence. First divergence takes place where flies have totally different stimulus exposure and that continuous exposure develops a more suitable hexagonal facets by evolutionary point of view are necessary for quick motion detection. Although they can only differ between bright and dark, they don't provide a very pure vision but this is necessary for them. The ectopic expression can be explained by their different nutritive exposure over the course of their evolution.
