In passive transport, how does increasing temperature generally affect the rate of diffusion of small molecules in a fluid environment?

• A. It decreases the diffusion rate because molecules become denser and collide less frequently.
• B. It stops diffusion entirely once a higher temperature is reached because equilibrium occurs faster.
• C. It has no effect on diffusion rate because diffusion depends only on concentration gradient.
• D. It increases the diffusion rate because molecules have higher kinetic energy and move faster.

Answer: (D)