A mixture of glucose and starch solutions was placed in a length of dialysis (Visking) tubing and the tubing sealed. The tubing was then placed in a boiling tube containing distilled water. Two samples were immediately removed from this water (time 0 minutes) and tested with either iodine solution or Benedict's solution. This was repeated at 10 minute intervals for 30 minutes. The iodine solution gave an orange-brown colour each time. The table shows the results of the Benedict's test. time/minutes: 0 (blue), 10 (green), 20 (yellow), 30 (red) What may be concluded from these results? 1 The pores in the Visking tubing are too small for a starch molecule to pass through. 2 Glucose diffuses through the Visking tubing down a diffusion gradient. 3 Water diffuses into the Visking tubing.

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