Human skin darkest brown to the lightest pinkish-white hues. Human skin shows higher variation in color than any other single mammalian species and is the result of natural selection. Skin pigmentation in humans evolved to primarily regulate the amount of ultraviolet radiation (UVR) penetrating the skin, controlling its biochemical effects. The actual skin color of different humans is affected by many substances, although the single most important substance determining human skin color is the pigment melanin. Melanin is produced within the skin in cells called melanocytes and it is the main determinant of the skin color of darker-skinned humans. The skin color
What Is the What writes: "Over the course of many years, Dave and I have collaborated to tell my story... I told [him] what I knew and what I could remember, and from that material he created this work of art." The book is typical of Eggers' style: blending non-fictional and fictional elements into a non-fiction novel or memoir. By classifying the book a novel, Eggers says, he freed himself to re-create conversations, streamline complex relationships, add relevant detail and manipulate time and space in helpful ways—all while maintaining the essential truthfulness of the storytelling. However, not all critics were impressed. Lee Siegel sees