Someone once observed that quot;the difference between roles and groups is that a user can shift into and out of roles, whereas that user has a

Someone once observed that "the difference between roles and groups is that a user can shift into and out of roles, whereas that user has a group identity (or identities) that are fixed throughout the session".

1. Consider a system such as a Berkeley-based UNIX system, in which users have secondary group identities that remain fixed during their login sessions. What are the advantages of roles with the same administrative functions as the groups? (Vague answer will not be accepted).
2. Consider a system such as a System V-based UNIX system, in which a process can have exactly one group identity. To change groups, users must execute the newgrp command. Do these groups differ from roles? Why or why not? (Vague answers will not be accepted).