Which of the following is not a trace element in living organisms?

Carbon is considered a fundamental element in all living organisms, making it a primary component of biological molecules such as carbohydrates, proteins, lipids, and nucleic acids. It is essential for the structure and function of cells, serving as the backbone for organic compounds. In contrast, copper, iron, and zinc are classified as trace elements because they are required by organisms in small amounts for various biological functions. These trace elements play vital roles in processes such as enzyme activity and the synthesis of important molecules. Therefore, while copper, iron, and zinc are critical for life, carbon is a major element integral to the very composition of living tissues.