This article explains the use of the Sync button within your instructor dashboard.
The sync button helps you present the all activity data to the student participants in real time. In the example above, both the show correct answer and show answer choices statistics option are turned to no.
If the options were toggled to yes, then the effect will take place within that question.
However, if you toggle the options to YES and press the sync button, then the option will be automatically applied to all the questions and not just one. The feature makes presenting data easier when you go into presentation mode because it applies your desired settings in bulk.