Add “Explanations” to questions

"Explanation" is the last field that you can fill in when creating a question:

Here, you can add explanations, images, or links that help students further understand the question. The explanation shows up for students after they’ve attempted the question.

"Explanation" is important because it provides an opportunity for students to clarify misconceptions, or even re-learn the concept. Spaced retrieval is most effective for helping students retain concepts they've already learned, so you want to ensure that students have an easy way to learn the concepts behind a question whenever they miss that question.