What structural protein is primarily responsible for skin elasticity?

The primary structural protein responsible for skin elasticity is elastin. Elastin fibers are highly elastic and enable the skin to stretch and recoil, providing flexibility and resilience. This is crucial for maintaining the skin's firmness and allowing it to return to its original shape after being stretched, such as when moving or stretching.

Collagen, while also a structural protein, primarily provides strength and support to the skin, helping to maintain its structure and resistance to wear and tear. Keratin is another protein found in the skin, hair, and nails, offering protective qualities but does not contribute to elasticity. Melanin is a pigment that provides color to the skin and protects against UV radiation but is not involved in the elastic properties of the skin. Thus, elastin is the correct answer as it directly relates to the elastic nature of skin tissue.