Answer:
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
A constant is something that is kept the same throughout the course of a experiment. So I would guess C) because they are not doing anything special. If it’s not C then it is A. :)
