Final answer:
Hair color is created by the combination of two types of melanin, eumelanin and pheomelanin, which are responsible for darker and red pigments, respectively. The blend of these pigments results in a variety of hair colors, which can change over a person's lifetime due to factors like sun exposure.
Step-by-step explanation:
Hair color is the result of pigmentation from two types of melanin: eumelanin and pheomelanin. Eumelanin provides black and brown pigments, while pheomelanin gives hair its red color. The combination of these melanins results in the vast spectrum of hair colors we see among individuals. As a person ages, production of these melanins can decrease, leading to gray or white hair.
Hair Coloring Process
Each individual has a unique proportion of these pigments, which is genetically determined and can change over time. For example, exposure to sunlight can increase the production of melanin, darkening the hair. A person with both eumelanin and pheomelanin will have a hair color that is a mix of the characteristics provided by both types of melanin, such as a brunette with natural red highlights.