Iris's therapist points out that she is nervously laughing while telling the story of her friend's recent death. He has her engage in a dialogue with her laughter. Iris's therapist is most likely a therapist.

Sector is best defined as (part).

Americans often speak of their country as one of several large regions.  these regions are cultural units rather than governmental units --  formed by history and geography and shaped by the economics, literature and folkways that all the parts of a region share. what makes one region different from another? a region's multicultural heritage as well as distinct demographic characteristics like age and occupation make regions different and special. within several regions, language is used differently and there are strong dialects. there are also differences in outlook and attitude based on geography.