Final answer:
The variations in skin color among indigenous people from colder regions can be explained by natural selection and evolutionary adaptations to different levels of ultraviolet (UV) radiation.
Step-by-step explanation:
The variations in skin color among indigenous people from colder regions can be explained by natural selection and evolutionary adaptations to different levels of ultraviolet (UV) radiation. As humans migrated to regions with less UV radiation, their skin pigmentation became lighter in order to allow for greater absorption of Vitamin D, which is essential for bone health and immune function. This gradual change in skin color can be observed when traveling from locations closer to the equator to colder regions.