The document defines and describes different types of family structures, including nuclear families consisting of parents and children, extended families that include grandparents and other relatives, single-parent families headed by one mother or father, blended families formed when two adults with children from previous relationships unite, and foster families that take in non-biological children. It notes that single-parent families often occur due to death, divorce, separation or migration of one parent and that blended families involve the joining of two adults who have children from prior relationships.