Which of the following applies to human skin color?
a. heritable only people with the mc1r gene can make eumelanin, because people whose skin has little eumelanin do not have the mc1r gene.
b. has been in hardy-weinberg equilibrium since the tribe hominini first evolved production of pheomelanin is the dominant trait.
c. affected by the mc1r gene only affected by the mc1r gene if the person carries a mutated version of the gene.
d. polygenic trait discrete trait has evolved due to evolutionary processes such as natural selection.

A. Heritable

C. Affected by the MC1R gene

D. Polygenic trait

Has evolved due to evolutionary processes such as natural selection.

Explanation:

Human skin color is a polygenic trait as it is regulated by more than one gene. Each allele of these genes has an additive effect on the overall skin color of an individual. Therefore, the trait is a continuous trait, not a discrete one. The genes for human skin color are transmitted from parents to progeny which in turn makes it a heritable trait.

The gene MC1R codes for melanocortin 1 receptor and thereby, regulate the skin color of humans since melanocyte-stimulating hormone binds to the receptor to trigger the synthesis of melanin from melanocytes. Evolution of various skin color in human beings is regulated by natural selection which in turn favors the skin tone best suited under the prevailing climatic conditions of a particular human population  

Heritable

Affected by the MCR1 gene

Polygenic trait

Explanation:

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the overall balanced equation

6co2 + 6h2o > c6h12o6 + 6o2

sunlight energy

where: co2 = carbon dioxide

h2o = water

light energy is required

c6h12o6 = glucose

o2 = oxygen