Which factor does NOT influence the rate of diffusion in cells?

The factor that does not influence the rate of diffusion in cells is the color of the substance. Diffusion is primarily affected by physical and chemical properties of molecules and their environment. The concentration gradient (the difference in concentration between two areas), temperature (which affects molecular speed), and surface area (which provides more space for diffusion to occur) are all critical factors that determine how quickly molecules move from an area of higher concentration to an area of lower concentration.

Color, however, does not impact the actual movement of particles. It is a property related to how substances absorb and reflect light but does not affect the kinetic energy or behavior of molecules during the process of diffusion. Therefore, while concentration gradients, temperature, and surface area directly influence diffusion rates, color remains an irrelevant factor in this context.