Is it possible to change the line spacing of the answers in a quiz activity?
I like to use 36px font size for the answers as my books are for early readers. But when I do this, the bottom of the 'check' and 'reset' buttons disappear. And I would like to space the lines further apart - e.g. when I use 36px font in the text on page, I set the line space to 52px.

I can't help, unfortunately. I too would like to see more flexibility in the Quiz widget—even in comparison to the old widget on iBooks Author this is extremely limited. Hopefully more options will come soon!