When it comes to hair and eye color, there is a wide range of natural variation. Some colors are more common than others, and some are so rare that they are considered to be unique. The rarest hair color is red, which is found in only about 1-2% of the population. The rarest eye color is green, which is found in only about 2% of the population.
There are a number of factors that can affect hair and eye color, including genetics, ethnicity, and environmental factors. However, the exact cause of rare hair and eye colors is not fully understood. Some researchers believe that rare hair and eye colors may be caused by mutations in genes that control the production of melanin, the pigment that gives hair and eyes their color.