U.S. Air Force Lt. Col. Mark Duff, 633rd Medical Group family health physician, prepares for a staff member to begin drawing blood during a blood drive at Langley Air Force Base, Va., June 2, 2015. As a joint operation, the Armed Services Blood Program has many components working together to collect, process, store, distribute, and transfuse blood worldwide. (U.S. Air Force photo by Airman 1st Class Devin Scott Michaels/Released)