1) Analyze a few examples showing how life expectancy, child mortality, and income per capita was significantly upgraded for the majority of humans as a result of the Industrial
Revolution (1760-1840).

this question your asking is true hope this and you get a 100 percent : )

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."