Final answer:
The Manhattan Project was a top-secret program in which American scientists developed an atomic bomb.
Step-by-step explanation:
The subject of the question is History.
The Manhattan Project was a top-secret program in which American scientists developed an atomic bomb. It was kept a secret from the entire executive branch except for President Roosevelt and Vice President Truman.
The project did not involve the rapid construction of the Pentagon; rather, it focused on the development and production of nuclear weapons.
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