The lowest point in an economic contraction is called
a. a peak.
c. a recession.
b. a trough.
d. a depression.

your answer would b. the missisipi river

hope i you : )

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."