The phenomenon of particles moving from an area of high concentration to an area of low concentration is called diffusion. This natural process occurs due to the random movement of particles and continues until equilibrium is reached. Diffusion plays a critical role in various biological processes, such as the exchange of gases in the lungs and the distribution of nutrients within cells. Understanding diffusion is essential in fields ranging from chemistry to biology, helping to elucidate how substances move and interact in different environments.