What age were soldiers supposed to be to fight in the army during the Civil War?

18 years old

Explanation:

To remember this is when they were drafted into the army they said if they were old enough to fight then they should be old enough to vote.

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."