Which sequence correctly describes the chemical steps in a permanent wave?

• A. Reducing agents provide pigment; base cream ends.
• B. Oxidizing agents break disulfide bonds, and reducing agents re-form them.
• C. Reducing agents break disulfide bonds, and oxidizing agents re-form them.
• D. Reducing agents break disulfide bonds, and oxidizing agents in the neutralizer re-form them.

Answer: (D)

In a permanent wave, the key process is breaking and then re-forming the bonds that give hair its shape. A reducing agent is used first to open disulfide bonds between the cysteine amino acids in the hair. This breaking allows the hair to be reshaped around perm rods. After the hair is shaped, an oxidizing agent in the neutralizer is applied to re-form those bonds in their new configuration, locking in the curl or wave. This re-formation happens specifically in the neutralizer, which is why mentioning the neutralizer is important.

That’s why the best choice states that reducing agents break disulfide bonds and oxidizing agents in the neutralizer re-form them. The other options mix in unrelated ideas (like pigment or base cream ends) or incorrectly describe which agent breaks bonds, or omit where the re-forming occurs.