If students have answered all of the questions, but are going back to review questions, it is easy to accidentally submit a quiz with no warning.  It would be great to either move the button to a different area of the screen (currently, it is right below the "Next" button) or add a warning about submitting, even if all the questions have already been answered (this is particularly important if there is only single attempt for the quiz.  

Similiar concerns have been raised in a different conversation, but it appears to have been marked "completed" just based on the initial comment, not subsequent ideas.  

https://community.canvaslms.com/t5/Idea-Conversations/Warning-when-submitting-quiz-not-based-on-timi...