Which of the following is an example of biomolecules?

Biomolecules are organic molecules that are essential for life and are typically found within living organisms. They include carbohydrates, lipids, proteins, and nucleic acids, all of which play crucial roles in biological processes.

Carbohydrates serve as energy sources and structural components, lipids serve as important energy reserves and are key components of cell membranes, proteins perform a vast array of functions including catalyzing biochemical reactions and supporting cellular structure, and nucleic acids (DNA and RNA) store and transmit genetic information. Together, these biomolecules are foundational to the structure and function of cells and thus are classified as biomolecules.

In contrast, options that list salts, minerals, water, air, vitamins, and enzymes either include inorganic substances or do not solely refer to the major categories of organic biomolecules that are central to biological processes. While vitamins and enzymes contribute to physiological functions, they fall more into specific roles within the broad categories of proteins or coenzymes rather than defining classes of biomolecules. Therefore, the option that specifically names the primary groups of biomolecules is the most accurate choice.