Once a quiz is completed, a user will be shown how many words were answered incorrectly and how many words were answered correctly.  This view will look like the below screenshot.  A user can tap on See Results which will provide a list of both correct and incorrect words.  Once you click See Results you will also be given the option to Share (iOS) or Email (Android) these results to an email address so that you have those words on record.  Once a user closes a quiz completely, there is no way to review the results. So be sure to utilize this option if you would like to work on the words you have answered incorrectly.