What were some of the elements of japan that were unifying?

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."

i believe the answer is: true

our brain need to reach a certain level of development   before it could interpret and understood sound with high difficulties. to proof this, we just need to pay attention in musical preference between children and adults. it is far less likely that children would enjoy things such as orchestra or rock band as much as adults due to the difference in this ability.