Final answer:
Alkaline chemical hair relaxers, along with thioglycolate permanent waves, break disulfide bonds in the hair to allow for styling changes. This process involves reducing agents and oxidizing agents to first disrupt and then re-form these strong covalent bonds.
Step-by-step explanation:
The correct answer to the question is A) Alkaline chemical hair relaxers. Thioglycolate permanent waves and alkaline chemical hair relaxers both work by breaking disulfide bonds within the hair. In both processes, a reducing agent is used to break these bonds. In the case of thioglycolate permanent waves, ammonium thioglycolate is utilized to reduce the disulfide bonds, allowing the hair's alpha-helices to shift position. Following that, an oxidizing agent, typically hydrogen peroxide, is applied to re-establish the disulfide bonds in their new configuration, effectively setting the hair in its new shape.
Disulfide bonds in hair structure are strong covalent bonds that are crucial for maintaining the hair's curl and texture. Breaking and reforming these bonds through chemical processes allows for temporary or permanent change in hair style, such as curling or straightening. The relative strength of disulfide bonds compared to hydrogen bonds explains why certain bond-breaking interventions are more lasting than others.