3. Cause: The spirit of the Renaissance spread in Europe

Explanation:

The Renaissance is an important event in European history that stretched from the 14th century to the 17th century.  It was preceded by the Middle Ages in Europe and eventually led to the major events of the Age of Enlightenment.  In historical terms the Renaissance is important because it led to a major shift in European thought and worldview.  This shift eventually led to the developments of the Enlightenment and set the stage for the modern western worldview. While the Renaissance is considered to have begun in the city-states of the Italian peninsula in the 14th century, the main ideas of the movement eventually spread to all of Europe by the 16th century.  The most significant changes that emerged as a result of the Renaissance can be seen in European architecture, art, literature, mathematics, music, philosophy, politics, religion and science.  Intellectual thought in these fields flourished during the timeframe of the Renaissance and led to many people questioning long held beliefs about each.  This created an environment of discovery and curiosity in which new ideas were constantly being introduced and tested.  Historians have been studying how, where and when the ideas of the Renaissance spread from its start in Italy to the rest of Europe.

the indians crossed artificial boundaries, setting the stage for conflict

cruel, heartless

explanation: