Final answer:
The piggyback wrap technique is used to add consistent curls to long hair by using perm rods, benefiting from the natural structure of the overlapping cells in the shaft of human hair.
Step-by-step explanation:
The benefit of wrapping hair in a piggyback wrap involves a technique used to add curls to the hair by using perm rods. This method allows for an even and consistent curl from the root of the hair to the ends. It is especially useful for long hair, as it manages to provide uniform curls without leaving any straight sections that sometimes occur with standard wrapping methods.
Given that the shaft of human hair is composed of overlapping cells, the piggyback technique effectively coaxes the hair into a curl along the entire shaft, resulting in a natural and cohesive style. It's also worth noting that hair serves various functions such as insulation, protection, and sensory input, making every hair care technique, including piggyback wrapping, part of a broader understanding of maintaining healthy and functional hair.