Exercise for mobile devices: Science or art

This question has been included in the course for participants who are accessing the course through a mobile device that is not compatible with drag-and-drop questions.  It covers the same content as the question above (Drag-and-drop exercise: science or art) but uses a format that is easier to use on a mobile device.  You only need to attempt this question if you were unable to complete the drag-and-drop question.