👉 The fluid, often referred to as blood or lymph in the context of circulatory and lymphatic systems respectively, is a complex mixture primarily composed of water, but also includes proteins, nutrients, waste products, cells, and various other substances. In the circulatory system, blood is a vital fluid that transports oxygen, nutrients, hormones, and immune cells throughout the body while also removing carbon dioxide, toxins, and cellular waste products. The lymph fluid, on the other hand, is part of the lymphatic system and serves a similar transport function but primarily aids in immune response by carrying white blood cells that fight infections and removing excess fluids from tissues, helping to maintain fluid balance in the body.