Answer:
Vatican City (I know it has city in the name lol)
Explanation
Trust me on this one though haha
The land mass is technically a country because of the Lateran treaty of 1929, which made Vatican city an independent state under the Holy See.
I'd have to say gas because it usually doesn't change at all
It supports current flowing because when the water in the ocean heats up the current goes in a circle
Hope this helps:) good luck!