The question is, if 100 years have passed, will the hair turn black again or will it remain white for life ???

 When a person is under 30 years of age, his hair is black and when he is old, his hair is white.

 

 the answer:

 As we get older, the pigment melanin that causes the black color in our hair starts to disappear, therefore our hair turns white or silver due to the depletion of this pigment.

 Melanin is the pigment that colors our skin and hair.

 Now it depends on the chemical composition of your hair how much pigment they have and when this pigment will die off and when your hair will be white or silver.

 All this information is stored in our genes as long as we have this pigment and as soon as this limit is crossed our hair becomes white or silver due to their deficiency.  And it has nothing to do with stress or reading.  Hair turns white when they cross their limits.  Otherwise not!

 Usually at the age when our grandparents have gray hair, our hair is white.

 Also, it is a myth that after a hundred years, the hair starts to turn from white to black.  Once the hair turns white or silver, no return is possible.

 Another question was why Pakistanis are getting bald so fast, the answer is that

 Lack of protein in the diet and stress are one of the main causes of hair loss and in Pakistan due to severe malnutrition and unhealthy diet which contains a lot of protein, a large part of the population quickly becomes bald.  A large portion of our population prefers unhealthy carbohydrates to base samosas instead of eating base eggs and proteins, which can be a major cause of baldness.