1) Russia is the world's largest country in area.
Does Russia is the world's largest country in area?
Russia is the world's largest country, isn't it?
2) The climate in Siberia is continental.
Does the climate in Siberia is continental?
The climate in Siberia is continental, isn't it?
3) It was warm in the South.
Was it warm in the South?
It was warm in the South, isn't it?
4) The head of the state is the President.
Does the head of the state is the President?
The head of the state is the President, isn't he?
5) The head of the government is the Prime Minister.
Does the head of the government is the Prime Minister?
The head of the government is the Prime Minister, isn't he?
Думаю, правильно, удачи