Answer:
it's related to the factors of diffusion, in this case...
the molecule is small, the mass of it is a factor of diffusion, since it's smaller, it can diffuse quickly, since it has less weight, so it moves faster.
When the cell increases in size, the volume increases faster than the surface area, when there is more volume and less surface area, diffusion takes longer and is less effective.
i think the answer is A.5
