Final answer:
In societies where slaves were interred alongside their owners, it can be inferred that slaves were used in burial practices as sacrifices or companions in the afterlife.
Step-by-step explanation:
In societies where slaves were interred alongside their owners and some slaves were beheaded as grave gifts, it can be inferred that slaves were used in burial practices as a form of sacrifice or as a means of providing companionship or service in the afterlife. The inclusion of slaves in burial rituals suggests a belief in the importance of social hierarchy and the continuation of power and status beyond death. This practice can be seen in ancient civilizations such as ancient Egypt, where pharaohs were buried with servants and attendants.