The liquid known as the universal solvent is water. Due to its polar molecular structure, water can dissolve a wide range of substances, making it essential for various chemical reactions. This property allows water to facilitate biological processes, transporting nutrients in living organisms and supporting various ecosystems. Water's ability to dissolve ionic compounds and polar molecules enables it to support life by enabling chemical reactions necessary for biological functions. Its role as a solvent is critical in maintaining cellular environments and driving metabolic pathways, demonstrating why it is often referred to as the universal solvent in chemistry and biology.