Animations, question reveals, timers, numbering, watermarks, backgrounds and transitions in a single pass. For one change at a time, the single tools are quicker.
Slides with their own animations are left alone. On question slides, the existing answer reveal is kept and plays after the new steps.
Answers are matched to question slides in order: the first question slide gets the first answer. If a slide already reveals its own answer, that reveal is kept and the key is used to double-check it.
Each text box grows only as far as its text still fits inside it. Headers, footers and slide numbers are left alone.