This essay delves into the adulthood stage of human development, examining biological and psychological changes from adolescence to death. It explores various psychological theories, including Piaget's and Erikson's, to understand human thoughts, emotions, and behaviors. The essay also discusses sociological theories, focusing on social interaction and the development of self-perspective. It analyzes conflict perspective, functionalism, and symbolic interactionism to illustrate how society influences individuals. The paper emphasizes the importance of logical thinking, problem-solving, and understanding human behavior during adulthood. It concludes that adulthood is a crucial stage for learning, adapting, and making informed decisions, with theories providing a framework for understanding self and others. Desklib offers more resources for students, including past papers and solved assignments.