By selecting Question On the Fly, you can ask a question spontaneously and have it recorded in a screen capture, without closing out of your presentation application. For example, you could be using PowerPoint or Keynote in slide show mode, decide to ask an unplanned question mid-session, and ask it using the Question On the Fly option without ever having to exit or close your PowerPoint or Keynote slide show.
A screenshot will be taken when polling begins and will be saved in i>grader along with the question title and the correct answer (if you chose to designate one).