Why flat and not round?

From:  "Dave"

Why is pubic and facial hair flat and the rest of our hair round?

amr shalakani gave us his professional opinion: 

cause they are different....they are hormone dependant and the structure of the hair follicles themselves are much different....that's why u do get your scalp hair at a much earlier age than the pubic and facial ones those start at puberty....ie) it's when your hormones start to kick in.