Final answer:
Chemical relaxers change the shape of the hair by breaking down disulfide bonds, which are stronger than hydrogen bonds. Disulfide bonds are covalent bonds that hold different protein chains or loops within a single chain together.
Step-by-step explanation:
When using a chemical relaxer, it changes the shape of the hair by breaking down disulfide bonds. Disulfide bonds are strong covalent bonds that hold different protein chains or loops within a single chain together. Breaking these bonds allows the hair to change shape.
In contrast, hydrogen bonds are another type of bond found in hair, but they are much weaker than disulfide bonds. Heat is sufficient to break hydrogen bonds, which is why using a hair straightener can temporarily change the shape of the hair, but it is not permanent.