The answer to this question is separated
It is d. If it was adaptation, the organism would have stayed in order to adapt. The species moved in order to not go extinct. It can not be speciation, because a new species was not made. It is stimulus. It experienced too much heat, so it left.
No there are no vacuoles in a human but there are in a plant but not humans.
Yes because the dominant genes would cover up the recessive ones
In short, because the UV rays damage skin cells, which increases the risk of a mutation possibly leading to skin cancer.
Hope this helps.