What is the process of diffusion?

Diffusion is a fundamental process in biology that describes the movement of molecules. The correct choice highlights that diffusion involves the movement of molecules from an area of high concentration to an area of low concentration. This movement occurs due to the natural tendency of particles to spread out evenly in a given space, driven by random molecular motion.

As molecules collide with one another, they move from crowded areas where they are in higher concentrations to less crowded areas, ultimately achieving dynamic equilibrium where concentrations are equal across a space. This process is essential for various biological functions, such as gas exchange in the lungs, the movement of nutrients and waste in and out of cells, and the overall maintenance of homeostasis within organisms.

Understanding diffusion is crucial because it illustrates how substances naturally flow and how this movement affects cellular processes, which is central to many biological systems.