However, the structure of lymphatic tissues vary according to the particular type of lymphatic tissue or organ they form a part of - (a), (b) or (c) above, and possibly also it's location in the body-especially in the case of (c) Lymph (Fluid).
The exposition is the portion of a story that introduces important background information to the audience; for example, information about the setting, events occurring before the main plot, characters' back stories, etc.
An essential element of historical fiction is that it is set in the past and pays attention to the manners, social conditions and other details of the period depicted.