What is the function of collagen in the skin?

Collagen is a crucial protein in the skin's structure, functioning primarily to provide firmness and elasticity. It serves as one of the main building blocks of skin, helping to maintain its strength and resilience. As we age, the production of collagen decreases, which contributes to the formation of wrinkles and sagging skin.

The other options focus on different roles in skin health: color is influenced by melanin, not collagen; protection against UV rays is primarily provided by skin cells and melanin; and fat storage is accomplished by adipose tissue, rather than collagen. Thus, the core role of collagen in maintaining skin firmness and elasticity makes it integral to the skin's overall appearance and health.