While you read up on vdj, know that the heavy chain has the vdj and there is dna rearrangement. know the l and h chains are made separately in the cytoplasm by means of disulfide ! the last step is the addition of the carbohydrate moiety. (look and remember my capital
second, at first, all b lymphocytes carry igm specific then after undergo class switching to the others (if you were lost here, you really need to know immuno and review)

  i think colonial period |-/

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.