Which of the following best
describes how genes can be regulated in the body?

Both species are mammals and therefore they share genome regions and gene families that are conserved in the course of evolution.

Explanation:

Synteny enables to identify conserved genome regions between species by aligning their DNA sequences. For example, the human and chimpanzee genomes share about 95-98% of synteny (sequence similarity) in their DNA sequences. In this case, a whole-genome sequence similarity of 80 % is evidence that both species are relatively closely related and share a near common ancestor. Indeed, it is expected that the most part of the remaining 20% represents mutations associated with the fixation of neutral alleles (i.e., neutral mutations) and therefore have no evolutionary meaning.