Columbus's voyages started a chain of events that would eventually lead to a society in (blank) based on representative government  and religious tolerance. A. Africa
B. Europe.
C. North America
D. South America

 North America.

Explanation:

answer; the edward snowden leaks of nsa classified material;

d. i assume the underlined word is "role." reformat if it isn't.

explanation:

role is closest to part because when replacing words, "playing a vital decision," "playing a vital activity," and "playing a vital dollar" don't make logical sense. the only meaningful choice is "playing a vital part."

this fits one of merriam-webster's definitions of role: "a function or part performed especially in a particular operation or process."