hello,  i have brown hair
Brown hair is awesome!  Interestingly, the strands of brown hair are thicker than those of fair colored hair.
i never knew that , i figured it all hair is the same except the color of it
Not so!  But brown hair is the second most common human hair color though.
let me guess, black is the most common 
Bingo!  Yes, it is!  And brown hair actually varies from light brown to almost black!