At any point during the quiz, you can view a summary of your quiz. Questions you've answered will be faded out and identified by a checkmark icon [1], while unanswered questions will be bolded and identified by a question mark icon [2].
You can also view the due date for the quiz [3]. In the sidebar, the quiz due date refers to the autosubmit date, which can be a specified Until date or the last day of the course. This is not the due date set for when the quiz will be marked late.
You'll also see a timer showing your progress on the quiz. For untimed quizzes [4], the quiz shows as the elapsed time. If you are taking a timed quiz [5], the timer shows the running time and counts down until time expires.