what event prompted the international community to begin the process of defining genocide as a crime

The Nazis systematic murder of Jewish people in the Holocaust during WWII. It was created by a Polish Raphäel Lemkin in 1944 in a book about crimes against humanity in occupied Europe during WWII.

Explanation:

so they can differentiate themselves from others as they saw themselves as the superior race. the star was basically a symbol that meant you are a less of a person than i am because of my race. the star was also degrading for those who had to wear it because they were aware of this and the nazis used the notion to make them feel less like a person.