All the biological macromolecules contain carbon, hydrogen and oxygen. however, most do not contain nitrogen. the category that contains nitrogen are a) lipids. eliminate b) proteins. c) carbohydrates. d) unsaturated fats.

B) Proteins

Lipids and Carbohydrates only contain carbon, hydrogen, and oxygen.

Unsaturated fats are a type of monomer for lipids, meaning they as well are only made up of carbon, hydrogen, and oxygen.

during the process of dna replication, brdu can replace thymidine and incorporate into the newly synthesized dna, cell proliferation thus can be reflected in the extent of brdu incorporation.