What does "heat capacity" measure?

"Heat capacity" is a term that refers to the amount of energy required to raise the temperature of a substance by a certain amount, typically one degree Celsius. This concept is crucial in understanding how different materials respond to heat. Various substances have different heat capacities, which influence how they absorb heat energy and how quickly they can change temperature.

When considering the context of the other options, while the transport of heat energy is relevant in thermodynamics, it does not define what heat capacity is. The rate of heat production pertains to the speed at which heat is generated, which is separate from the concept of how much energy is needed to increase temperature. Lastly, the amount of fuel in an area relates to the potential for combustion and energy release in fire scenarios, but does not describe the thermal characteristics of materials as heat capacity does. Thus, the correct answer emphasizes the specific relationship between energy input and temperature change within a substance.