Final answer:
The main elements that make up the chemical composition of human hair are carbon, oxygen, hydrogen, and b) Sulfur.
Step-by-step explanation:
Sulfur is found in the proteins that make up hair, specifically in a bond called a disulfide bond. These bonds give hair its shape and texture. When heat is applied to hair, such as with a hair straightener, the disulfide bonds are broken, causing the hair to lose its curl. However, this method of hair straightening is not permanent because the bonds can reform when the hair is exposed to moisture.
Overall, the major elements found in human hair are carbon, oxygen, hydrogen, and sulfur. These elements form the different compounds and molecules that give hair its unique properties. The correct answer is b) Sulfur.