Answer:
Huh? I don't understand but my guess is 2?
More than one staff can be grouped with a bracket or a brace to create a system. The bracket typically groups independent parts to form a system. In the example below, the voice parts (soprano, alto, tenor, and bass) are connected with the bracket to create visual grouping of the voice parts.
Matrilineality is the principle of descent in (15%) of the worlds societies- hope this helps :)