They used interchangeable parts. This made the mass production possible and caused it to happen.
To end World War 1, and to have Germany pay reparations for causing the war.
Random attacks by Indian tribes. The frontier had swamps-to-mountainness terrain. Seeds didn't work in all parts of America, some lived healthy in one area while the same seed could die somewhere else there.
<span>Alexander Graham Bell
hope this helped</span>
