What is a person who is not a citizen but has official permission to live and work in a country

The answer is legal immigrant. There are many ways on which a person can become a legal immigran some of which are: job sponsorship, marriage, asylum seekers and so on. This is a very controversal topic in the US under Trump’s administration. Usually a legal immigrant is a holder of a ‘green card’ document.

Americans often speak of their country as one of several large regions.  these regions are cultural units rather than governmental units --  formed by history and geography and shaped by the economics, literature and folkways that all the parts of a region share. what makes one region different from another? a region's multicultural heritage as well as distinct demographic characteristics like age and occupation make regions different and special. within several regions, language is used differently and there are strong dialects. there are also differences in outlook and attitude based on geography.