Concept:The biuret test is used to detect the presence of proteins in a sample.
Explanation:In this test, a sample is treated with
CuSO4 (copper sulphate) in a basic solution.
Proteins contain two or more peptide bonds.
These peptide bonds react with the copper(II) ions to form a purple or violet complex.
If protein is present, the solution turns purple.
If no protein is present, the solution remains blue.
Therefore, the biuret test specifically identifies proteins rather than carbohydrates, amines, or alkanoates.
Answer:B. proteins