what are at least two critical functions that fluid within the body provides
Extracellular fluid
The extracellular fluid provides the medium for the exchange of substances between the ECF and the cells, and this can take place through dissolving, mixing and transporting in the fluid medium.[6] Substances in the ECF include dissolved gases, nutrients, and electrolytes, all needed to maintain life.[7] The ECF also contains materials secreted from cells in soluble form, but which quickly coalesces into fibres (e.g. collagen, reticular, and elastic fibres) or precipitates out into a solid or semisolid form (e.g. proteoglycans which form the bulk of cartilage, and the components of bone). These and many other substances occur, especially in association with various proteoglycans to form the extracellular matrix or the "filler" substance between the cells throughout the body.[8] These substances occur in the extracellular space, and are therefore all bathed or soaked in ECF, without being part of the ECF