0_Apprentice
What color is your hair? 
1_Wizard
My hair is brown, the second most common hair color.
0_Apprentice
What is the first most common hair color and what is the third? 
1_Wizard
Black is the most common hair color and I am not sure about the third, probably blonde.
0_Apprentice
What causes people to have different hair color? 
1_Wizard
Higher levels of the dark pigment eumelanin and lower levels of the pale pigment pheomelanin result in darker hair.
0_Apprentice
What causes the different levels of melanin? 
1_Wizard
Melanin is a group of natural pigments found in most organisms. How much a person has is hereditary.