Who names new bern?
modern czechoslovakia
southern france
Switzerland
scotland

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."

answer; the three types of research;

answer/// playing;

it makes your voice or whatever you are doing with it and makes it louder. doing this makes people pay attention to you and makes them hear what you say therefore they have a better chance of following you or listening to you. therfore establishing dominance.