What two proteins provide strength, form, and flexibility to the skin?

Collagen and elastin are the two proteins that are essential for providing strength, form, and flexibility to the skin. Collagen is the most abundant protein in the skin and forms a fibrous network that adds structure and firmness, helping to maintain the skin's integrity and resilience against stretching and sagging. Elastin, on the other hand, allows the skin to stretch and return to its original shape, providing the skin with elasticity and flexibility. Together, these proteins play a crucial role in maintaining the overall appearance and health of the skin, contributing to its youthful look and ability to withstand environmental stresses.

Other options do not provide the same dual benefits in relation to skin structure and flexibility, making collagen and elastin the correct choice for this question.