Which of the following is NOT a recognized area of biological study?

Astrophysics is the field that focuses on the physical properties and behavior of celestial bodies and the universe as a whole, which is distinctly outside the realm of biological study. Biological studies primarily concern the systems and processes of living organisms, touching on various disciplines such as the molecular level (biochemistry), the study of plants (botany), and the inheritance of traits (genetics). In contrast, the areas of biochemistry, botany, and genetics are all integral parts of biology, each addressing different aspects of life sciences, from chemical processes within organisms to the diversity of plant life and the mechanisms of heredity. Thus, identifying astrophysics as the option that does not belong to biological study aligns with understanding the distinction between the natural sciences and their various branches.