Once you finish
growing to adulthood, neurons stop dividing. Hair follicle cells constantly
divide throughout your lifetime since they are constantly producing cells that
become part of the hair itself as they die. So in an adult, the rate of cell
division for neurons is zero (although there is some counter-evidence but it is
certainly very low) while the hair follicle rate is much higher on the order of
once every few days or faster.
cause I believe that because of the populations and polutions that is cause of humans we are now lack of protective shield and green gases within our atmosphere
