What were the contributions of the harappan civilization?

your answer is

to dominate europe

and i know for a fact it can't be the others

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.