What is the role of the concentration gradient in the diffusion process?

The concentration gradient is a crucial factor in the diffusion process, as it creates the driving force that causes particles to move. In diffusion, particles tend to move from an area of higher concentration to an area of lower concentration. This movement occurs because molecules and ions are in constant motion, and they will naturally disperse evenly throughout a given space.

When there is a concentration gradient, meaning a difference in concentration between two areas, the particles will move down this gradient, seeking to achieve equilibrium where the concentration is uniform. Therefore, the correct answer highlights that diffusion continues until the concentrations on both sides equalize, with particles moving toward the area of lower concentration as they strive to balance out the differences.

Options suggesting that concentration gradients do not impact diffusion or that they reverse the direction of diffusion are incorrect since diffusion is fundamentally driven by the presence of a concentration gradient. Additionally, asserting that particles move towards higher concentrations misrepresents the basic principle of diffusion.