Final answer:
Option C. The porosity of hair determines its ability to absorb chemicals during a perm. Hair porosity is key in how effectively the hair absorbs perm solutions and the resulting effectiveness of the perm. Highly porous hair is more susceptible to absorbing perm solution, which can impact processing time and potential damage.
Step-by-step explanation:
When giving a perm, the porosity of hair determines its ability to absorb chemicals. Porosity refers to how well hair can absorb and hold moisture, which in turn affects how it reacts to chemical treatments like perms. Applying a perm involves using chemicals to break and reform the disulfide bonds within the hair structure, which gives the hair a new shape. The porosity of the hair is crucial because it influences how the hair absorbs these chemicals, which determines the effectiveness and longevity of the perm.
Permanent waves and chemical straightening both rely on similar chemical processes. The disulfide bonds in hair provide its shape and texture, and breaking these bonds allows the hair to be reshaped. During a perm, the hair is wrapped around forms to curl it, and the chemical solution is applied to set the new shape. Temporary waves, by contrast, involve the disruption of hydrogen bonds, which reform upon drying. This is a less permanent change because these bonds are easily broken by water or heat.