Question

what happens during heat transfer?
heat always flows from warm to hot.
heat always flows from cool to warm.
heat always flows from warm to cool.

Explanation:

Heat transfer occurs due to a temperature difference. According to the second law of thermodynamics, heat naturally moves from an area of higher temperature (warm) to an area of lower temperature (cool) until thermal equilibrium is reached.

Answer:

Heat always flows from warm to cool.