Final answer:
100% lack of pigmented hair makes hair appear white, commonly due to the absence or reduction of melanin production.
Step-by-step explanation:
100% of pigmented hair equates to virtually no pigmented hair, which tends to appear white. The lack of pigmentation is due to an absence of melanin, typically caused by genetic factors or a decrease in melanin production as one age. The percentage of pigmented hair is inversely related to the extent of graying or whitening of the hair.
In the case of fetuses, lanugo is the fine, colorless hair that covers their body before they are born. This lanugo is shed around the time of birth. People usually lose pigment in their hair, leading to gray or white hair, as they age because melanin production by melanocytes decreases.