Distinct molecules called agglutinogens (a type of antigen) are attached to the surface of red blood cells. There are two different types of agglutinogens, type A and type B. Each type has different properties.
MDB: Geodatabase. The geodatabase is a collection of geographic datasets of various types, with the most basic types being vector, raster, and tabular data. There are three types of geodatabases: file, personal, and ArcSDE. Geodatabases are the native data format for ESRI's ArcGIS.
projection files, if data is not in a standard coordinate system, so that data will properly line up in ArcMap. All data is created in some coordinate system. (define) the map projection file that will render your data in the right location in ArcMap in relation to other data. been created using a standard projection.