You can find the student answer history in the results view for each individual student. It's also from here that you export the students' answers. Learn more about exporting student answers here.

To access the student answer history, click on Results > Student's name in the participant list > Answer history (as shown in the image below). There, you can navigate through the saved backups and restore to an earlier text if desired. You do this by selecting the version and then clicking on the arrow icon to the right of the history menu.