ghettos and camps were two different things.
yes
Westerbork transit camp and Theresienstadt ghetto
None, there were things in the ghetto which were better than in the camps, but there were no benefits; there was no guarantee of food, or of housing, or of work.
to kill jews and put them in concentration camps and also to hold them until they finished building the death camps.
They were taken from the ghettos to extermination camps, where they were killed.
to hold the Jews until they finished building the death camps
The question is a bit vague. It was the home of Warsaw's Jewish population and when the Nazis decided to send them to the camps, they targetted the Ghetto.
The Jewish ghetto police secured the deportation of Jewish people to the concentration camps. They were also not permitted to carry weapons.
they were taken to the ghetto and then to the concentration camps
The Nazi ghettos came to an end when the remaining population was deported to extermination camps. The last major ghetto to be liquidated in this way was the Lodz Ghetto in August 1944.
A ghetto was a part of a city, especially a slum area, occupied by a minority group or groups. The Nazis, in WW2, force Jews, and others they considered as undesirables into such ghettos.
concentration camps or death camps Edit: Like the above said, they were sent to concentration camps. Although, if they were healthy the Jew was then send to work camps, but before this they lived in the ghettos. (or they had to go hide.)