Final answer:
The dermis, which Hannah is modeling, is primarily made up of fibroblasts that produce the tough connective tissue providing strength and elasticity to the skin.
Step-by-step explanation:
Hannah is modeling the dermis, which is the thick inner layer of skin located beneath the epidermis. This layer consists predominantly of fibroblasts. Fibroblasts are responsible for producing the tough connective tissue that comprises the bulk of the dermis, facilitating strength and elasticity to the skin. This connective tissue includes collagen and elastin fibers, making the dermis a vital layer for skin integrity and resilience. The dermis also hosts various structures such as blood vessels, sweat glands, hair follicles, and oil glands.