Which of the following is classified as an organic acid that contains nitrogen?

The classification of amino acids as organic acids that contain nitrogen is accurate because amino acids possess both amine (-NH2) and carboxylic acid (-COOH) functional groups. This unique structure contributes to their role in biological processes, as they are the building blocks of proteins and participate in various metabolic pathways.

The presence of nitrogen in their structure differentiates amino acids from other organic acids. While formic acid, acetic acid, and citric acid are all organic acids characterized by their carboxylic acid groups, they lack the amine group that defines amino acids. Therefore, the distinction lies in the presence of nitrogen within the molecular structure of amino acids, making them a vital category of organic compounds involved in numerous physiological functions and processes.