Answer the question about supporting details that follow the textbook passage. Contemporary American society has a variety of markers of entrance into adulthood. There are legal definitions: at 17, young people may enlist in the armed forces; at age 18, in most states, they may marry without their parents' permission; at 18 to 21 (depending on the state), they may enter into binding contracts. Using sociological definitions, people may call themselves adults when they are self-supporting or have chosen a career, have married or formed a significant relationship, or have founded a family. There are also psychological definition. Cognitive maturity is often considered to correspond with the capacity for abstract thought. Emotional maturity may depend on such achievements as discovering one's identity, becoming independent of parents, developing a system of values, and forming relationships. Some people never leave adolescence, no matter what their chronological age. The main idea is