👉 A valid fluid is any liquid that can circulate within a living organism, typically blood in animals or plasma in humans. These fluids play crucial roles in transporting nutrients, oxygen, hormones, and waste products throughout the body. Blood, for instance, is a type of fluid that carries red blood cells (for oxygen transport), white blood cells (for immune response), and platelets (for clotting). Other valid fluids include synovial fluid, which lubricates joints, and cerebrospinal fluid, which cushions the brain and spinal cord. Essentially, any liquid substance that can move through the circulatory system and perform essential physiological functions qualifies as a valid fluid.
