How have relations among humans become so complex since early times?

Answer the question above which is the assignment topic: How have relations among humans become so complex since early times? Also, answer 3 sub-questions: In different periods of world history what methods have some human groups used to impose conditions of social and economic inferiority on others? What conditions or circumstances led to women achieving greater political and social equality in many countries in the twentieth century? Humans have practiced many forms of social bondage, such as slavery, serfdom, and debt peonage. Do systems of social bondage still exist today, and what forms may they take?