What determines a Mandatory item

I have built a Unit for a course that has 2 pages.

On page 1 I have included 15 questions (they are not Mandatory or Assessable) and all questions are 'Answer field' types.

After a student answers all 15 questions and goes to page 2 and clicks Done when they are returned to the Module summary page it displays '0 of 15 Mandatory elements completed'

And the 'percent of unit completed' (on the right) indicates 12% has been completed - although all the questions have been answered.

The only other elements I have on this page are Text elements.

What determines a Mandatory element in CoursePress Pro?

Please help.