How does isolation relate to speciation

Isolation such as geological can cause speciation because if one species where divided into two because of geological reasons, they're likely to change their behaviors and physical appearances to match that region.

XRXr

Explanation:

The sex chromosomes of females is denoted by XX. With that alone, it cannot be the first and the second choice. Now taking into account that the sex linked trait is heterozygous that means that there is a dominant and recessive allele of the trait, Rr. This means that the last option is wrong.

The answer is then XRXr