Both drugs had been previously recommended for approval 14-0 by members of FDA's Anti-Infective Drugs Advisory Committee. The significance of two new antibiotics in four weeks? We've recently been averaging one antibiotic every three years.
More melanin presence in the skin makes the skin appear black, and less melanin will make the skin appear less black. White people have very little melanin synthesized by their skin. So, the color of the races is because of some difference in the quanitity of the melanin pigment in our body. That is all.
The most common form of biological melanin is eumelanin, a brown-black polymer of dihydroxyindole carboxylic acids, and their reduced forms. Most are derived from the amino acid tyrosine. Eumelanin is found in hair, areola, and skin, and the hair colors gray, black, blond, and brown. In humans, it is more abundant in people with dark skin. Pheomelanin, a pink to red hue is found in particularly large quantities in red hair, the lips, nipples, glans of the penis, and vagina.