In 1968 Garrett Hardin described the tragedy of the commons. The classic example of the commons is a pasture where any community member can graze his or her livestock. What would be the modern equivalent of the commons?

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; archaeologists;

answer; their own memory abilities;

answer; menopause;