Known as the these teenagers initially needed a military escort to attend classes.

1. seasonal

2. frictional unenployment

3. the number of the labor force multiplied by 100 and then subtract the number of unemployed.

4. 4%

5. an increase in prices

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."