What role does sunscreen play in a skincare routine?

Sunscreen plays a vital role in a skincare routine primarily by protecting the skin from the harmful effects of ultraviolet (UV) radiation. UV rays can lead to various forms of skin damage, including sunburn, increased risk of skin cancer, and premature skin aging, which manifests as wrinkles, fine lines, and sunspots. By forming a protective barrier on the skin's surface, sunscreen helps to shield against both UVA (known for aging effects) and UVB (known for causing burns) rays. This protective effect is essential for maintaining skin health and preventing the signs of aging, making sunscreen an indispensable element of an effective skincare regimen.

While other options do mention important aspects of skincare, they do not specifically highlight the critical protective function of sunscreen regarding UV damage and its role in preventing skin aging. This underscores why the correct answer focuses on the protective benefits sunscreen offers to the skin.