Tonicity refers to the ability of a solution to affect the shape and volume of cells through osmosis. It is determined by the concentration of solutes in the solution compared to the concentration of solutes inside the cell. There are three main types of tonicity: isotonic, hypertonic, and hypotonic. An isotonic solution has equal solute concentrations, while a hypertonic solution has a higher concentration outside the cell, causing it to shrink. Conversely, a hypotonic solution has a lower concentration outside the cell, leading to swelling or bursting. Understanding tonicity is crucial in various fields, including biology and medicine. For example, when administering intravenous fluids, healthcare professionals must choose the appropriate tonicity to maintain cell health. Using an isotonic solution helps keep cells stable, while a hypertonic solution can be used to reduce swelling. In contrast, a hypotonic solution may be used to hydrate cells. Proper knowledge of tonicity ensures effective treatment and