Which is an environmental factor that effects skin color in humans?

One significant environmental factor that affects skin color in humans is ultraviolet (UV) radiation from sunlight. Increased exposure to UV radiation stimulates the production of melanin, the pigment responsible for skin color, leading to darker skin tones as a protective adaptation against skin damage and skin cancer. Conversely, populations in regions with less sunlight typically have lighter skin, which allows for better synthesis of vitamin D in low UV conditions. This adaptation highlights the interplay between environment and human Biology in determining skin color.