Final answer:
Tribes use an integrative mechanism to form organizations that connect individuals from different families. Anthropologists refer to these integrative groups as age sets, age grades, or sodalities.
Step-by-step explanation:
Tribes differ from bands due to the presence of an integrative mechanism that forms organizations, uniting members from different families for common purposes. These integrative groups, according to anthropologists, are referred to as age sets, age grades, or sodalities. These structures help integrate the tribe beyond immediate family ties and provide a means for social cohesion, authority distribution, and decision-making processes.