What area of study does thermodynamics belong to?

Thermodynamics is fundamentally concerned with the principles governing heat and energy. It explores how energy is transferred and transformed, particularly in the context of heat, which is a form of energy. The study involves understanding the laws of thermodynamics that describe how energy moves within physical systems and the changes that occur as heat is added or removed.

In thermodynamics, pivotal concepts such as temperature, enthalpy, entropy, and internal energy are analyzed to explain processes such as phase changes, chemical reactions, and the efficiency of engines. Therefore, the area of study focused on heat and energy captures the essence of thermodynamics, making it the correct choice.