Which of the following molecules is directly formed from polypeptides?

Polypeptides are biological polymers formed by the linking of amino acids through peptide bonds. When polypeptides undergo proper folding and structural modifications, they ultimately become functional proteins. Proteins serve a variety of critical roles in biological systems, including serving as enzymes, antibodies, structural components, and regulatory molecules.

The key process that converts polypeptides into proteins involves the folding into specific three-dimensional shapes, which is essential for their function. Therefore, while amino acids are the building blocks of polypeptides, the polypeptides themselves specifically assemble into proteins.

The other options listed—carbohydrates and nucleic acids—are different types of macromolecules that do not directly arise from polypeptides and have distinct structures and functions within biological systems.