This slider appears on the top right of every question box. It indicates whether a question will be shown to students (and its grade counted) or not. If it is to the right with the teal indicator, it will appear in the lesson.
Moving the slider to the left turns off the question. If the question is turned off, its Default Point Value becomes 0 and you will a see the message "This question has been excluded from the lesson."
You can hide or show any question, whether it was written by you or Science Interactive!