1. A group is defined as two or more interacting and interdependent individuals who come together to achieve particular objectives. Groups can be formal, with defined structures and roles, or informal, guided by organizational goals. 2. Groups develop norms and roles that influence member behavior and ability to achieve goals. Norms are patterns and expectations for how the group will function, while roles like leader, facilitator, and member are necessary components. 3. Interpersonal relationships within groups are important for member well-being and social support. Developing strong listening skills, honesty, ability to handle disagreements, and expressing gratitude can help relationships. Transactional analysis looks at how people communicate through different ego states.