What do you think the biggest struggle was for people living in the South? (Think about how they made living, how many ACTUALLY owned slaves versus those that didn't) 2 sentence minimum.

option d is correct. corroborated sources of historical evidence   is necessary to validate a claim about an event in history.

historians tend to use written sources, but audio and visual materials as well as artifacts are important objects that supply information to modern historians.

historical sources are usually divided into two categories: primary and secondary sources. depending on the historian's intent, some sources shift their designation. determining what type of sources toimplement, and the level of credibility and reliability of those sources, is a significant step in critical thinking for the historian.

explanation:

c. troops marched forward in close formation against newer, more accurate weapons