Why would a researcher use primary source instead of a secondary source when analyzing a historical event?

Which choice describes some of the difficulties john adams faced as presiden

According to winthrop in city upon a hill which of the following is not a benefit of living according to gods commands

Revolutionary war. date battle result april 19, 1775 june 17, 1775 dec. 31, 1775 aug. 27, 1776 oct. 26, 1776 dec. 26, 1776 sept. 11, 1777 sept. 19, 1777 oct. 4, 1777 oct. 7, 1777 dec. 5, 1777 june 8, 1778 sept. 16, 1779 march 29, 1780 sept. 28, 1781 can i get the name of the battles and the result on the battles on the dates above