Center for Army Lessons Learned Director Col. Christopher Keller answers online questions about the new "Army 21 -- Brigade Combat Teams" multimedia, interactive-learning tool during an Association of the United States annual meeting webinar Oct. 15, 2020. To learn more about Army 21, view the demonstration video at https://drive.google.com/file/d/1dbBVGotNq5y_22dHfqYj-ahK8sIGX1eF/view?usp=drivesdk (U.S. Army photo by Randi Stenson, MCCoE Public Affairs)