Final answer:
Salts are not one of the major classes of organic compounds in the human body; the major classes are carbohydrates, proteins, lipids, and nucleic acids.
Step-by-step explanation:
The student asked which of the following is not one of the major groups of organic substances in the human body: proteins, salts, lipids, nucleic acids. The major classes of organic compounds crucial to human structure and function are carbohydrates, proteins, lipids, and nucleic acids. Therefore, salts do not belong to this list as they are inorganic substances. These organic compounds are constructed from various combinations of carbon atoms covalently bonded to hydrogen, usually oxygen, and frequently other elements. Understanding the role and composition of these compounds is essential in Biology for grasping the biochemical basis of life.