The document discusses different types of marriage including monogamy, serial monogamy, polygamy, polygyny, polyandry, and group marriage. Monogamy allows one spouse at a time while serial monogamy involves multiple marriages but only one legal spouse at a time through divorce and remarriage. Polygamy allows multiple spouses and can take the form of polygyny where a man has multiple wives or polyandry where a woman has multiple husbands. Group marriage involves all members of the group being married to each other. Factors like agriculture, religion, and social norms influence which types of marriages are commonly practiced in different cultures and societies.