Which group was responsible for determining the borders of african colonies and later countries?

The correct answer is the attendees of the Berlin Conference.

The attendees of the Berlin Conference in 1884-1885 were largely responsible for the creation of artificial borders in Africa.

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.