examples of big questions from the past

Some of you have asked for examples, so here you go.  Check out the comments to the following posts:

https://drprestonsrhsenglitcomp13.blogspot.com/2013/05/whats-your-big-question.html

https://drprestonsamlitsmhs1617.blogspot.com/2016/08/whats-your-big-question.html

https://drprestonsamlitsmhs1920.blogspot.com/2019/08/whats-your-big-question.html