Columbian Exchange: The widespread transfer of plants, animals, culture, human populations, technology, diseases between the Americas and the Old World in the 15th and 16th centuries; like downloading multiple apps onto your phone from different sources.
Nomadic Lifestyle: A way of life where people move from one place to another instead of settling permanently; similar to using your new app (horse) to explore different areas (lands).
Buffalo Hunting: A primary source of food and materials for many Plains Indians before horses were introduced; akin to an older version of an app that was used before the new one came along.