    Sentence 4: What did Paul Baran develop          Sentence 2: Starting in the late 1950s, American  computer scientist Paul Baran developed the  concept Distributed Adaptive Message Block  Switching with the goal to provide a fault-  tolerant, efficient” routing method —_for  telecommunication."messages as part of a  research program “at“the RAND Corporation,  funded by the US Department of Defense.                   