The last option: World War II
Hey there!
At the Wannsee conference in 1942 the Nazis made plans to find a final solution to the "Jew problem". In their opinion, there were too many jews in their empire and they were looking for a way of getting rid of them (It sounds - and is - cruel, but unfortunately that's the truth). They found their 'solution' in the form of concentration and death camps.
The rules discussed were a follow-up of the Neurenberger laws (1935) which had as a purpose to isolate the Jews.
~ I hope this answer helps you!
Thomas Jefferson was the main author of the declaration of independence
The constant, or dependent variable is the variable that does not change in the experiment.