Hello!
The answer is: C. Difference in temperature
Why?
Heat transfers to another substance until the thermal equilibrium is reached, it means that the average temperature between the substance is almost equal or equal. Heat transfer means that the temperature will be transferred from the higher temperature substance to the lower temperature substance.
There are three ways of heat transfer:
- Conduction: When the substances are in contact.
- Convexion: When the heat transfer involves liquid or gas displacement. For example, the sun heating the surface, causing a displacement of warm air and cold air.
- Radiation: When thermal radiation happens, it does not involve any contact between surfaces or substances. For example, the heat transferred by a light bulb.
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