Describe how skin pigmentation is determined, and also how it is affected by exposure to the sun.

pigmentation is determined by the amount of melanin in the skin. Without melanin, the skin would be pale white with shades of pink caused by blood flow through the skin. The extra melanin makes your skin look darker or sun-tanned. In some cases, the sun causes an uneven increase in melanin production, which produces irregular coloring  of the skin. The sun can also cause a permanent stretching of small blood vessels, giving your skin a mottled, reddish appearance.

Explanation:

d.

explanation:

the cladogram shown here shows similarities and differences among several classes of vertebrates. anatomically, the four have limb structure as their common ancestor. we might separate the mammals from the other three classes because they a) divergent; do not lay eggs b) identical; are warm-blooded c) varied; a four chambered heart d) homologous; have mammary glands