Human populations in low-uv environments tend to have more lightly pigmented skin. one explanation is that the selective pressure for dark skin decreases as uv intensity decreases. at the same time there is selection for lighter skin to absorb more uv radiation, which is needed for vitamin d production. what evidence supports the vitamin d hypothesis for the evolution of lighter skin tones? a. lightly pigmented people tend to be at higher risk of vitamin d deficiencyb. red hair and light skin are typical of people of northern european descentc. lightly pigmented people cannot synthesize vitamin d in high-uv environments, such as equatorial africa. d. indigenous peoples living at high latitudes have darker skin, but they eat foods rich in vitamin d.

Lightly pigmented people tend to be at higher risk of vitamin D deficiency

Explanation:

BACKGROUND KNOWLEDGE:

Human skin is the largest organ of the body which makes boundary line between environment and internal conditions.  Human skin cell produces pigment called melanin when ever it is subjected to Sun. More the melanin pigment produced more will be the skin darkens. Ultraviolet (UV) radiations also come from Sun and responsible for more pigmentation.

ANSWER EXPLANATION:

According to the question darkly pigmentation only occurs when their is high level of UV radiations. High level of UV radiations are also responsible for Vitamin D production.

People with lightly pigmented means that there environment has low level of UV radiations which are the requirement of Vitamin D production. Hence due to low UV radiations peoples with light pigmentation's are also be at higher risk of vitamin D deficiency

the answer is c cumulus. cumulus clouds can be seen on a gray and rainy day, because cumulus clouds create thunderstorms. give me brainliest if right.