A common laboratory investigation involves putting a solution of starch and glucose into a dialysis bag and suspending the bag in a beaker of water, as shown in the figure below.

The investigation is aimed at understanding how molecular size affects movement through a membrane.

Which of the following best represents the amount of starch, water, and glucose in the dialysis bag over the course of the investigation?

From the figure, it appears as though glucose has entered the bag. Only one answer shows this change. We can further verify that starch remains constant over the course of the experiment, since starch does not appear in the solution. Finally, water enters the bag and expands it.