blood type. Any of the four main types into which human blood is divided: A, B, AB, and O. Blood types are based on the presence or absence of certain substances, called antigens, on red blood cells.Also called blood group.lood type. Any of the four main types into which human blood is divided: A, B, AB, and O. Blood types are based on the presence or absence of certain substances, called antigens, on red blood cells.
Amendments are sent to the legislatures of the states by default. Only one amendment, the 21st, specified a convention. In any case, passage by the legislature or convention is by simple majority. The Constitution, then, spells out four paths for an amendment:
Article Five gives two ways to amend, or change, the Constitution. 1  Congress can write a change, if two-thirds of the members in each House agree. 2  The state governments can call a convention to write changes, although this has not happened since 1787.