The greatest unifying force of the ottoman empire was a common religion.
Egenuity says C.) Behavior . . . Cognitive Processes ^-^
Thats a pretty logical question. they took over Poland. and they had more than one camps in different areas, and they wanted to kill off the Jews because Hitler blamed the Jews for German losing WWI. so the camps were to put the Jews in labor and kill them, do some research you'll find the answer.
discovered how to control the yellow river