“there may be a time when we are powerless to prevent injustice, but there must never be a time when we fail to protest.” - elie wiesel
what does this quote mean?

We must never fail to speak out against it.

Explanation: let me explain, if you fail to speak out against injustice those who committed will do so again and again and again. Speaking out against it draws attention to the issue and eventually it will be stopped because someone had heard you.

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; conditional stimulus will trigger a conditioned response;