<span>Urban centers rarely are in mountainous areas where travel is difficult, for example, and almost never where there is no water, which is essential to human survival as well as transportation. </span>
The ancient people were moving west.
The bridge that you are referring to was called the Bering land bridge which is now the Bering Strait. During the Ice age, though this area was covered in ice which made the sea levels drop and emerged the land bridge, the land bridge was covered with grasses and low shrubs which provided food for the mammoth, horses, caribou, and bison. It is believed that the ancient people followed these grazing animals from beringia (which is now SIberia) and into America, they are believed to be the first inhabitants of America. Over time the weather got warmer and the glaciers started melting and the bridge started disappearing into what we now call the Bering strait this all happened about 11,600 years ago
Heat<span> can be transferred from one place to another by conduction </span>in <span>solids, convection of fluids like liquids or gases, and radiation. A </span>temperature<span> difference </span>in a system<span> causes </span>heat<span> to </span>move<span> from higher to lower temperatures</span>
As the Cold War heated up in the 1950s, the United States made decisions on foreign policy with the goal of containing communism. To maintain its hegemony in the Western Hemisphere, the U.S. intervened in Guatemala in 1954 and removed its elected president, Jacobo Arbenz Guzman, on the premise that he was soft on communism.
