Which of the following focuses on the study of the systems and functions of the body?

The study that focuses on the systems and functions of the body is physiology. This branch of biology examines how the different systems within the body operate and interact, allowing for the maintenance of homeostasis and overall health. It delves into processes such as how organs function, how systems like the muscular, nervous, and circulatory systems coordinate, and how various bodily functions are regulated.

Understanding physiology is critical for fields such as medicine, nursing, and other health professions, as it provides insights into how body functions can be affected by diseases and how various treatments may interact with these processes. By studying physiology, one gains a comprehensive view of how the body works at both the systemic and cellular levels.