What is the most important reason for citing a source when quoting it directly?

How was louis and clark expedition event unfolding and what was going on

Which of the following led to a continuation of the treatment in the excerpt above? a)the brutality of the trans-atlantic african slave trade. b)spanish repression after violent native uprisings in new spain during the 16th century. c)european competition to quickly establish colonial holdings in the new world. d)the reliance of the spanish on native americans to provide labor under the encomienda system.

What does the term “escalation” refer to?