How was the north different from the south before the civil war?

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:

in the 1800s, locomotives powered by steam made transportation faster and cheaper. the resulting rapid growth of railroads led to the connection of the atlantic and pacific railroad in oklahoma city in 1897.

in the last years of the century, the improvement of steam-based engines the expansion and growth of railroads. this growth increased when the companies started to build and expand, such as the atlantic and pacific railroad, which connected new mexico with california, and missouri with oklahoma. many of these new networks were built in oklahoma, and these changes transportation henceforward.

whats the question? im not quite understanding your question.