Why do you think we tend to focus more on the Southern civil rights movement than on the
Northern movement?

Because there was much more oppression against African Americans after slavery. For example segregation, lynching, and clear racism. While the north had subtle racism in comparison to the south..

Explanation:

the answer is b. osage.

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: