Question

while using biuret reagent, you test not only the mystery food sample, but also gelatin and water. which solution acts as a positive control? gelatin water mystery food sample

Explanation:

The Biuret reagent tests for proteins. Gelatin contains proteins, so it will give a positive reaction and can act as a positive control. Water has no proteins and the mystery food sample is unknown. A positive - control is a sample known to give a positive result for the test.

Answer:

gelatin