Final answer:
Layering is the texturizing technique used to create expansion and fullness by removing weight at the base area of the hair, typically used on clients with thick or heavy hair to add shape and movement while maintaining length.
Step-by-step explanation:
The type of texturizing technique used to create expansion and fullness while removing weight at the base area is known as 'layering'. Layering can be performed using various cutting tools such as shears, razors, or thinning shears. The process involves cutting the hair to different lengths throughout the head, which removes bulk from the bottom layers of the hair and allows the top layers to sit with more volume and lift. This is particularly effective for clients with thick or heavy hair who want to maintain length but reduce the appearance of heaviness and add shape and movement to their hairstyle.