without a government a country would not be control and managed
It's called 'anarchy'.
A government that rules a country form year to year without great change is usually a republic government. The power is usually with the people but only some of the people rule.
no because without tax the country can survive
Somalia, North Korea
The United States.
Depends on the country. Without a specific country this question is too broad to answer. Re-ask with a specific country or countries.
To keep it simple an illegal immigrant is someone who moved to the country from Another Country without the government's permission. They would have to hide in a container on a ship or swim there or something.
Vatican City, Singapore, Nauru
A sovereign government
A country's government is call a national government.
North Korea is often cited as the only country in the world without a newspaper. The country heavily controls its media, and all newspapers are state-owned and serve as propaganda tools for the government.