sentences: "In the last decades of the 20th century, the Department of Defense business model was configured to support a military dependent on large-scale weapons systems and prepared for sustained, predictable battlefield engagements in specific parts of the world.With the challenges that face the U.S. military in the 21st century, the DoD established the Business Transformation Agency to allow the defense business enterprise to adapt, flex, and react effectively to the needs of its modern joint warfighter.