👉 Water, the universal solvent, is a key fluid in all living systems due to its unique properties. It exists primarily as liquid at Earth's temperatures, enabling the transport of nutrients and waste in biological organisms. Water's ability to dissolve a wide range of substances makes it essential for chemical reactions within cells, facilitating processes like metabolism and photosynthesis. Its high specific heat capacity helps regulate temperatures in both aquatic environments and living organisms, while its cohesive and adhesive properties support phenomena like capillary action in plants and the formation of water droplets. These characteristics underscore water's critical role as a fluid in sustaining life and maintaining ecological balance.