What does physiology study?

Physiology is the branch of biology that focuses on the functions and processes of living organisms. It examines how various systems within organisms operate, including their interactions and mechanisms that maintain homeostasis. This encompasses everything from cellular functions to how entire organs and systems work together to enable life, reproduction, movement, and response to stimuli. By studying physiology, scientists gain insights into the complex behaviors and processes that sustain life, making it a key area of study in understanding living organisms.

The other options, while related to biology and the life sciences, do not accurately capture the primary focus of physiology. Cell structures pertain more to cellular biology or cytology, genetic variations relate to genetics and evolutionary biology, and environmental interactions focus on ecology. Each of these areas is important, but they do not address the core inquiry of how organisms function in terms of their physical and biochemical processes.