If Biuret reagent is added to a solution, and it reacts to produce a pink to purple color, this indicates the presence of ________ in the solution.

A) lipids
B) glucose
C) protein
D) cholesterol
E) starch

Biuret reagent is commonly used to test for the presence of proteins in a solution. When the reagent reacts with peptide bonds in proteins, it forms a complex that absorbs light and appears pink to purple in color. Lipids, glucose, cholesterol, and starch do not react with Biuret reagent in the same way, so their presence would not result in a color change.