A solution that resists changes in pH is called a buffer solution. Buffers are essential in maintaining stable acid-base balance within biological systems. They do this by neutralizing added acids or bases, preventing drastic fluctuations in pH that could disrupt essential biochemical reactions. In living organisms, buffers maintain homeostasis, which is crucial for optimal enzyme function and overall cellular activity. Examples of buffer systems include bicarbonate in blood and phosphate buffers in cellular fluids.