Those regions closest to the equator, have people whose skin has evolved or adapted to the more intense sunlight.
(Those regions closest to the equator; have; people whose skin has evolved or adapted to the more intense sunlight) (people; has evolved; ) (people; adapted; to the more intense sunlight)
Those regions closest to the equator people people
have has evolved adapted
people whose skin has evolved or adapted to the more intense sunlight
to the more intense sunlight