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.
Geodatabases in ArcGIS can be stored in three different ways - as a file geodatabase, a personal geodatabase, or an ArcSDE geodatabase. Introduced at 9.2, the file geodatabase stores information in a folder named with a .gdb extension.