If you wish to show additional activity items such as "Question 1 - correct/incorrect" then "Question 2" - correct/incorrect" and so on, there does not seem to be a way to determine the order in which they will show to the teacher.
The "What's New in ClassKit - WWDC 2019" video shows this as an example at the 23:10 point of the video, but it doesn't seem possible to accomplish in code.
Even if the addAdditionalActivityItem calls are made in order so that each is added to the additionalActivityItems array in the order that you wish for them to display, they appear in a random order when the Teacher views the results of a completed activity.
The primaryActivityItem is always shown first, but the additionalActivityItems appear in a random order. Seems like we need a displayOrder property for CLSActivityItem similar to the property on a CLSContext. Is there any way to accomplish this as of now?