In each tube, a certain amount of a starch solution and a potassium iodide solution was added. Then, each test tube was placed in three different baths, each with different temperatures: an ice water bath, a warm water bath, and a very warm water bath. After the solutions adjusted to the temperatures of the baths, they were taken out, and a certain amount of a potassium persulfate solution was added to each tube. After the potassium persulfate solution was added, the time it took for each reaction to occur was measured. For this experiment, the control variables were the amount of starch solution, the amount of potassium persulfate solution, the concentration of the substrate, and the absence of a…