Which principle of teaching was not applied?

To determine which principle of teaching was not applied, we need to consider the specific context of the lesson or teaching scenario. Common principles include engagement, differentiation, active learning, and clear objectives. If, for instance, students were not actively participating or the lesson did not cater to diverse learning styles, it could indicate a lack of active learning or differentiation. Without more context, it's challenging to identify the exact principle that was neglected.