Which of the following substances primarily contributes to skin elasticity?

Elastin is the primary substance that contributes to skin elasticity. It is a protein found in connective tissues that allows skin to stretch and return to its original shape. As a key component of the dermis, elastin provides the skin with its ability to endure mechanical stress while maintaining flexibility. The presence of elastin is essential for preventing sagging and preserving a youthful appearance, as it helps the skin resist the effects of aging and environmental damage.

While collagen is also important for skin structure and firmness, it mainly provides strength rather than elasticity. Vitamin C is crucial for the synthesis of collagen and has antioxidant properties that help protect the skin, but it does not directly contribute to elasticity. Similarly, retinol, a form of vitamin A, plays an important role in skin renewal and can improve the appearance of fine lines and wrinkles, yet it does not function as a primary contributor to elasticity. Thus, elastin stands out as the most significant factor in maintaining the skin's ability to stretch and recover.