Why was the manhattan project kept top secret?
the united states did not want great britain or france to know that it had nuclear technology.
no one was sure if the atom bomb would actually ever work and they didn't want negative feedback.
the allies were afraid that the technology would be stolen by spies belonging to germany or japan.
the united states was developing the technology illegally and with stolen technology and materials.

What is the main difference between primary and secondary sources? a. primary sources are historical documents, and secondary sources are modern-day documents. b. primary sources are derived from museums and archives, and secondary sources are created by history students and academics. c. primary sources are found in ancient places with a rich history, and secondary sources are found in historical journals and blogs. d. primary sources are created during a particular historical era, and secondary sources are created by studying primary sources.