Answer:
Diffusion takes place in this process where iodine and glucose molecule diffuses through the dialysis tubing whereas the starch did not. Diffusion takes place on the basis of the size of the molecules.
Starch molecules are large in size whereas iodine and glucose are much smaller therefore they are able to diffuse. If both iodine and starch would have diffuses through the tubing the color would change into dark purple by mixing thee both molecules.
