It is defined as person or citizen of the united states.
Not all rights of a citizen aer defined, for example. you have the right to breath and open and shut your own eyes...you do NOT have a right to become a US Citizen without the government's definition or obligation to "give" that person that right.
A citizen can petition their parents if the citizen is at least 21.
Yes. All legal authorities agree on this. There is an open question of whether a child of citizens NOT born on U.S. soil is also a natural born citizen, but no disagreement about this aspect of it.
Yes a Zambian citizen can marry a Us citizen and work in the us because the zambian citizen can obtain a citizenship by marriage and automatically become a citizen of us and is allowed and qualified to work there.
The child of a US citizen is considered a US citizen.
No. Marrying a US citizen does not make someone a US citizen.
If the function has been declared and defined, then the only remaining issue is scope, i.e. visibility.
he is a German born u.s. citizen
You are born one .
Yes, he is the US citizen.
No, I do not believe that you have to be a US citizen to act.