What is thermodynamics the study of?

Thermodynamics is fundamentally the study of energy transformations within physical systems. It examines how energy is converted from one form to another and how these transformations affect matter. For example, it explores the behavior of energy during processes like heating, cooling, phase changes, and chemical reactions.

By understanding energy transformations, thermodynamics provides valuable insights into how different systems achieve equilibrium, the direction of spontaneous processes, and the efficiency of energy utilization. This core principle is critical across various scientific fields, including chemistry, physics, and biology, enabling us to understand everything from mechanical systems to biochemical pathways.

The other choices, while related to aspects of energy, do not capture the broader scope of thermodynamics. Energy creation is not a process studied in thermodynamics since it does not create energy but rather converts and transfers it. Focusing on energy loss in reactions narrows the view to specific scenarios without considering the full realm of energy transformations. Lastly, metabolic pathways involve biological processes specifically, which could be studied within the framework of thermodynamics, but they represent only a subset of the overall study.