The law of thermodynamics states that when two objects of different temperature are in contact, heat energy will flow from the hotter to the cooler object.

Second.

Explanation:

There are four types or kinds of the laws of thermodynamics, but in this question we are actually considering the second law of thermodynamics.

The second law of thermodynamics, in a simple sense means that energies can flow in an equilibrate manner. It can also be stated as the total entropy of the universe. The second law is normal refer to as Law concerning Entropy.

Thus, filling the gap in the Question above. Note that the word written in capital letters is the missing word.

"The SECOND law of thermodynamics states that when two objects of different temperature are in contact, heat energy will flow from the hotter to the cooler object."