Human skin color is a polygenic trait, which means that multiple gene loci (with different alleles) are involved in its expression. It has been shown that there more than 350 genetic loci involved in determining skin color. Because of that, there is the enormous number of possible genotypes for the skin color and as a result, the phenotypes vary from the darkest brown to the lightest hues. Different populations have different allele frequencies of genes for human skin color, and the combination of these allele variations brings about complex and continuous variation in skin coloration. Natural skin color can change due to exposure to sunlight (becomes darker) and that is the way it adapts to intense sunlight irradiation (protection against the UV exposure).
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Answer:I think that answer is b
Explanation:
<h2>The Forearm</h2>
Explanation:
The proximal end of the radius illustrates the relationship of form and function. The cup-like surface of the radial head articulates with the rounded shape of the capitulum. This forms a joint that allows for movement of elbows and forearms.
Radius and ulna are the two bones of the forearm. Their proximal ends articulate and fit into the cup like end of the humerus. This forms a synovial joint called the elbow joint. The movement of this joint allows the forearms to supinate and pronate.
I chose the answer that said "Transition to socialist and communist government systems, and creation of labor unions."
