Someone, please answer this but I don't want some answer saying 'oh so I didn't get what you wanted, so I copied this off of blah blah blah.' yeah please dont =^= approximately how many billion cubic meters of water did China become in 1980? how much is it expected to views by 2030?

818 billion cubic meters in 2030

Explanation:

4.8 billion cubic meter/year in 1980

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."