Body fluids refer to a large number of water-based liquids contained in the human body, including intracellular fluids and extracellular fluids. In addition to containing a large amount of water, there are many ions and compounds. Which of the following are not body fluids? ['Sweat from a hot environment.', 'Plasma flowing in blood vessels.', 'interstitial fluid.', 'Lymph flowing in the lymphatic vessels.']