Why did president lincoln place general mclellan under the command of general halleck? a. mcclellan failed to capture richmond. b. mcclellan was responsible for the north's defeat at the second battle of bull run. c. mcclellan failed to defeat lee at antietam creek.

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 a. primary sources are historical documents, and secondary sources are modern-day documents.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.