Final answer:
Primary groups are small, emotionally connected groups that fulfill expressive needs, while secondary groups are larger, task-focused groups that serve instrumental functions.
Step-by-step explanation:
Primary groups are small, long-term, and emotionally connected groups that fulfill expressive needs. Examples of primary groups include families and close friends. On the other hand, secondary groups are larger, impersonal, and task-focused groups that serve instrumental functions. Examples of secondary groups include classrooms and offices.