Respuesta :
The study of chemicals is called chemistry.
The correct answer is A.
According to the law of thermodynamics, It states that heat transfers from the high temperature to the low temperature.
According to the question, heat transfer must require the temperature difference between the two systems and allow to flow from high temperature to low temperature.
Hence, the correct answer is A that is a difference in thermal energy
For more information, refer to the link:-
https://brainly.com/question/14698383