Why is an agenda useful for a meeting?

Why is an agenda useful for a meeting? How might a formal agenda be adapted to a meeting in your workplace, for example, with a human resources specialist to discuss benefits, or with another company entity? If not at work, then where have you seen a formal agenda used to drive a meeting to the conclusion?
addresses roles people fulfill in groups. Variables, such as a person’s own perceptions and expectations and the views of colleagues provide a foundation for the role(s) a teammate plays. Offered are categories of task-oriented roles, maintenance-oriented roles, and individual or self-oriented roles. in each of these categories are sub-roles. From your experience in groups professionally or otherwise, where have you seen any of these roles played out? How effective were they in advancing or retarding group success?
Identify how roles, needs, and diversity can affect teamwork.