Which of the following is NOT one of the main areas biochemists study?

The choice concerning the physical properties of metals is not considered one of the main areas that biochemists study. Biochemistry primarily focuses on the chemical processes and substances that occur within living organisms. This includes examining how the structure of biomolecules such as proteins, lipids, carbohydrates, and nucleic acids relates to their function, exploring metabolic pathways and the chemical reactions that sustain life, and understanding how organisms communicate through signaling molecules and biochemical pathways.

In contrast, while physical properties of metals may be relevant in other scientific disciplines, such as inorganic chemistry or materials science, they do not directly relate to the core concerns of biochemistry. Biochemists concentrate on the molecular and cellular underpinnings of biological processes rather than on the attributes of metals themselves. Therefore, this option stands out as distinct from the primary focus of the field.