Fill in the Blanks with Single Words or Single Letters

Fill in the blanks with single words or single letters.
Each of us carries our personal ____1____ that shares our body space (but is principally distributed within our ____2____) and that contains ____3____ times more cells than our body. These cells are foreign ____4_____ that are nevertheless tolerated by the body, largely by suppressing ______5______ ____6______ responses, notably those that depend on _____7____ receptors. Our personal _____1_____ is normally beneficial to us because some of the _____4_____ are beneficial to us in different ways. They can help us derived additional energy through the fermentation of undigested _____8______, help us break down _______9_____ , and they synthesize vitamins _____10_____ and _____11_____ for us. In ____12____ ____13____ diseases, however, an abnormal ____6____ response is directed against antigens carried by foreign ____4_____ within our ___2____ and that leads to accumulation of ____14____ blood cells within the linings of the _____15_____ , producing chronic _____16_______.