Which option best completes the statement: The size and shape of a curl is primarily determined by the perm rod size?

• A. Perm Rod Size
• B. Hair Density
• C. Elasticity
• D. Texture

Answer: (A)

Curl size is determined by the diameter of the perm rod you wrap the hair around. When you wrap hair on a rod, the hair is shaped to follow that rod’s circumference, and the bonds re-form to hold that shape as the wave develops. A larger rod diameter creates looser, bigger curls, while a smaller diameter yields tighter curls. Hair density, elasticity, and texture can influence how easily the hair takes the curl and how well it holds, but they don’t set the curl’s size—the rod size does.