Final answer:
The statement that resistant hair may not be saturated with one application of waving solution is true. Resistant hair has a cuticle layer that makes it difficult for the solution to penetrate, potentially requiring multiple applications for a permanent wave.
Step-by-step explanation:
The statement 'Resistant hair may not become completely saturated hair with just one application of waving solution' is true. Resistant hair refers to hair that does not easily allow a substance to penetrate its cuticle. In the context of temporary and permanent waving, the waviness relies on the disruption and reformation of disulfide bonds in hair strands. The hair's wave is temporary if the changes involve only the disruption of hydrogen bonds, which happens when water molecules slip into the hair fibers and form a new shape as they dry. For a more permanent change, a chemical solution must be applied to break and re-form the disulfide bonds.
Especially resistant hair might require more than one application of the waving solution to become fully saturated and to ensure that the disulfide bonds are broken and can then be reset into their new shape. This is because the cuticle layer may be more tightly packed or the overall structure of the hair can be less porous, making it harder for the solution to penetrate and facilitate the desired changes in texture.