When their needs are met, infants learn that relying on others is safe; when their needs go unmet, infants grow up to be less trusting. Bronfenbrenner’s ecological systems model challenges us to go beyond the individual if we want to understand human development and promote improvements. During the formal operational stage children, at about age 12, acquire the ability to think logically about concrete and abstract events. The teenager who has reached this stage is able to consider possibilities and to contemplate ideas about situations that have never been directly encountered. Physical Development in Adolescence (9-18 years) If you read it differently the second time (adding the second “the”) you just…