What is the skin nourished by, aside from blood?

The skin is nourished by lymph, which plays a crucial role in the immune system and in maintaining fluid balance in the body. Lymph is a clear fluid that circulates through the lymphatic system, carrying nutrients, oxygen, and immune cells to the skin and other tissues while helping to remove waste products. This process supports the skin’s overall health and ability to heal, as it keeps the skin hydrated and nourished.

While oxygen is vital for skin cell function and can be considered a nutrient in a broader sense, it is primarily delivered through blood rather than being a direct source of nourishment. Adrenaline and carbon dioxide do not serve as nourishment for the skin; instead, adrenaline is a stress hormone that can affect skin conditions and carbon dioxide is a waste product that is expelled from the body. Thus, the correct choice emphasizes the specific role of lymph in supporting skin health.