Party building and joint construction 1+3+x+n organizational structure, 1 why?

Party branches should make clear their main responsibilities. According to the "Notice on Promoting the Best Cases and Excellent Cases of Party Construction in Engineering Construction Enterprises" issued by China Construction Enterprise Management Association, we can see that. Party building should build an organizational structure of 1+3+x+n, and 1 is the main responsibility of the party branch to carry out party building activities around the production and operation center.