Specific heat capacity is defined as:

Specific heat capacity is accurately described as the heat required to raise the temperature of one gram of a substance by one degree Celsius. This definition encapsulates the concept of specific heat capacity, which is an important property of materials. It reflects how much thermal energy a substance can store and its resistance to temperature changes when heat is added or removed.

This property is crucial in many fields, such as meteorology, engineering, and even cooking, as it helps predict how substances will react under varying thermal conditions. Substances with a high specific heat capacity can absorb a significant amount of heat without experiencing a large increase in temperature, making them important for temperature regulation.

The other options do not correctly define specific heat capacity. For instance, phase changes, combustion, and cooling processes encompass different thermodynamic concepts, such as latent heat and heat transfer, but they do not specify the relationship between heat transfer and temperature change per unit mass, which is the essence of specific heat capacity.