Final answer:
The technique of cutting shorter lengths within the hair to create support and mobility is called layering. It's a hairstyling method that creates volume and movement.
Step-by-step explanation:
Cutting shorter lengths within the form of bulk and creating support and mobility is called layering. In the context of hairstyling, layering is a technique used to shape the hair, provide more volume, and enable movement. By cutting the hair at different lengths, the hairdresser creates a variety of layers that achieve the desired style and look for the client. This technique can help remove weight from the hair, enhance curls or waves, and give the hair structure.