Who formulated the zeroth law of thermodynamics?

What are extensive variables and what are intensive variables? What are these variables?

Can any system possess thermal energy?

Which of the following is not a thermodynamic coordinate?

The following three objects $(1)$ a metal tray,$(2)$ a block of wood,and $(3)$ a woolen cap are left in a closed room overnight. Next day,the temperature of each is recorded as $T_1, T_2$,and $T_3$,respectively. The likely situation is:

If $A$ and $B$ are in thermal equilibrium independently with a third system $C$,then what can be said about the systems $A$ and $B$?