【物理 - 筆記】Is heat always flows from a body with more internal energy to a body with less internal energy?

No, heat is not always flows from a body with more internal energy to a body with less internal energy. The fact is heat flows from a body with higher temperature to a body with lower temperature.

However, if the two objects are made of the same materials and are in the same size, then the statement that "heat flows from a body with more internal energy to a body with less internal energy" will be true. In this case, both bodies have the same heat capacity, and thus higher temperature means higher internal energy.