Heat that flows by conduction is the transfer of thermal energy between substances in contact. What must occur for this to happen?

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Heat that flows by conduction is the transfer of thermal energy between substances in contact. For this to happen, what must occur?

A) The two systems must be the same temperature.

B) The two systems must not be touching each another.

C) One system must have higher kinetic energy than the other system.

D) The thermal energy of one system must be the same as the thermal energy of the other system.