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.
SDC: Smart Data Compression. SDC is ESRI's highly compressed format, which is directly readable by ArcGIS software, but not by ArcView 3.x. Many ESRI Data and Maps datasets are natively in SDC format. With ESRI Data and Maps 2006, a standalone Data Distribution Application was included that converts SDC data files directly to shapefiles.