There are several ways to view quiz answers and results, or to mark them.
To view a specific course's quiz's results for all learners
Go to the course page and click into Reports.
Click on 'Filter', Add the 'Type' filter with just 'Quiz' selected.
Under the ACTIONS column, click on the '...' for any user whose quiz answers you wish to view/mark.
Select 'Mark Submission.'
To view a specific learner's results for all quizzes
Go to Administer->Enrolments.
Click on 'Filter', Add the 'Type' filter with just 'Quiz' selected.
Search for the student whose quiz results you would like to view or mark.
Under the ACTIONS column, click on the '...' for any user whose quiz answers you wish to view/mark.
Select 'Mark Submission.'
In either method, you can view previous attempts (if any exist) for a question by clicking on the 'View Previous Attempts' to the right of a question.
Additional Information:
Create a Quiz