What is the basic principle behind the chemical process of perming hair?

The correct answer focuses on how perming fundamentally changes the physical structure of the hair using chemicals or heat. During the perming process, specific chemicals are applied to the hair to break the disulfide bonds that hold the hair's natural shape. Once these bonds are altered, the hair can be reshaped into curls or waves by wrapping it around rods or rollers. After the hair is set in this new shape, another chemical is applied to re-establish the disulfide bonds in the new configuration, effectively "locking in" the curls or waves.

This explanation highlights the significance of both chemical and physical elements in achieving the desired texture change in hair, which is essential to understanding the perming process in a hairdressing context.