Straight hair or curly hair is based more on chemistry than environment. It’s made up mostly of proteins produced in a follicle, or sac, at the base of a single strand. Each protein contains the element sulfur, the atoms of which push toward each other to bond, or connect. If the atoms are far from each other, the protein bends and the hair curls. If the atoms are close, the protein does not bend and the hair is straight. So much for hair gel, eh?