Answer:
Diffusion is rapid for short distances but slow for long distances
Explanation:
Let's call t the time required for molecules in a solution to move from a to b, and d the distance between a and b. For what the sentence says
t ∝ √d where ∝ means proportional.
So, as the distance increases, the time of diffusion increases too, and the process is slow. So, diffusion is rapid for short distances but slow for long distances.
