Changing character states when submitting an answer

Hi...I know it's 8 years after this initial answer, but this was one of the first I saw when I googled this question so thought it might be worth an update for anyone else trying to do this!

Another way of doing this is to define new states for the character on the base layer called 'correct' and 'incorrect' (or whatever you want to call them!). Then add a trigger to the Correct and Incorrect  layers on the slide to change the character to the required state when the timeline starts on the layer. Be aware, however, if you move or flip the character in the base layer, the other states are not going to automatically change correspondingly, so worth checking each state fits in with whatever else is appearing on the correct/incorrect layers! For this reason, Helen's answer might be a better option as more straightforward to see what's going on on the layer, but thought worth mentioning this other solution as it might be useful in some situations (and this is how it was done on a project I was working on and it took me a while to work out what was going on!).