The correct answer to this question is C. The starch in the bag turned purple. This experiment is performed to help one understand the process of diffusion, as well as Semi-permeable membrane and Concentration gradient. It is the process of molecules and atoms moving from an area with high concentration to low concentration.
Diffusion occurs in physics. To perform this experiment, one would need a paper clip, dialyzes tubing, beakers, scissors, starch, and iodine. The starch turns purple due to the diffusion of the iodine that occurred when it was in the tube. The iodine was at a high concentration.