1 Simple molecules [molecule: A molecule is a collection of two or more atoms held together by chemical bonds. 2  It is the smallest part of a substance that displays the properties of the substance.
Eon has a number of meanings. In Astronomy, an eon refers to 1 billion (109) years. But it also refers to a very long, unspecified period of time, or specific geologic stages of the Earth.
In fact, that's almost entirely what it is. The original EO dealing with national defense resources preparedness was issued in 1939 (EO 8248) according to the National Archives. It has been superseded a number of times, starting in 1951 by nearly every President through Bill Clinton, and amended twice by George W. Bush.