"which statement best describes what would most likely be observed after 20 minutes?
(1)the contents of the dialysis tube would turn blue-black.
(2)the liquid in the beaker would turn blue-black.
(3)the dialysis tube would burst.
(4)there would be no change visible."

Option A, The contents of the dialysis tube would turn blue-black.

Explanation:

A dialysis tube placed in a beaker consisting of solution of water and starch. Here exchange of material will take place through membrane of dialysis tube.

The dialysis has low concentration of starch while the solution in which it is placed has a high concentration of starch. Thus, starch will start moving from the solution into the dialysis tube thereby converting it into blue-black color.

Thus, option A is correct