Starch molecules are too large to pass through the tubing into the beaker. Which errors could have caused starch to appear in the beaker despite this fact? Check all possible errors.

Starch should remain inside the tubing, so starch detected in the beaker suggests contamination rather than diffusion through the tubing. If the tubing’s outside was not washed after filling, starch could be carried into the beaker (A). Reusing droppers or using a beaker that still contains starch could also contaminate the beaker (B and D). Adding glucose to the tubing (C) would not cause starch to appear outside.

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