Read this and answer the question. If the question is unanswerable, say "unanswerable".

Female houses differed from male Dominican houses in a lack of apostolic work for the women. Instead, the sisters chanted the Divine Office and kept all the monastic observances. Their lives were often much more strict than their brothers' lives. The sisters had no government of their own, but lived under the authority of the general and provincial chapters of the order. They were compelled to obey all the rules and shared in all the applicable privileges of the order. Like the Priory of Dartford, all Dominican nunneries were under the jurisdiction of friars. The friars served as their confessors, priests, teachers and spiritual mentors.

What roles did the friars not serve as to the nuns?
unanswerable