The United States Ambassador to the United Nations<span> is the leader of the U.S. delegation, the </span>U.S. Mission<span> to the </span>United Nations. The position is more formally known as the "Permanent Representative<span> of the </span>United States<span> of America to the </span>United Nations<span>, with the rank and status of </span>Ambassador Extraordinary and Plenipotentiary<span>, and Representative of the United States of America in the </span>Security Council of the United Nations<span>"; it is also known as the U.S. Permanent Representative, or "Perm Rep", to the United Nations</span>
Before Polk, the United States and Mexico had boundaries along the Rio Grande River. Texas and Polk claimed that America's southern border ran down to the river south of the United States' positon back then. They had a war, but Mexico lost and U.S kept expanding.
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The role that the Railroads played in the Southern Economy was that "They Shipped materials to Northern Markets" Their main goal was to ship crude materials.
D, mass production was made easier by assembly lines because products could be made faster
