Research has indicated that seventh- and eighth-graders who outscored most high school seniors on a college aptitude test had begun at an unusually early age.

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."

the answer is : the nut cases won't quit battling and their recurrence of flights will going to continue as before despite the fact that the battles are less hazardous now because of their bills have all of a sudden been blunted.   in the falcon dove diversion, two creatures will drive towards one another to crush one another, among the two one will win and other will swerve. in this way, clearly, the battle will be dependably there between two creatures for the assets or mate.