Final answer:
The heat quality that varies with substances and is needed to change their temperature is called specific heat, which is a unique characteristic for each substance.
Step-by-step explanation:
The heat quality that varies with different types of substances and is needed to change the temperature of a substance is called specific heat. Specific heat is the amount of heat energy required to raise the temperature of 1 gram of a substance by 1 °C (or 1 K). This characteristic property is unique for each substance and plays a significant role in heat transfer processes. Substances with a low specific heat can change temperature more easily because they need less energy per unit mass to increase their temperature.