Edicate the answer choice that best completes the statement or answers the question Railroads in the North and South
Miles of Railroad Track
1840
1850
1860
wawili wawili
wake wawili
walil
South North
One train equals 1,000 miles of tracks
Based on the graph, which of the following statements is correct?
Oa. In 1840 there were more miles of railroad track in the South than in the North
Ob. In 1850 the South more than tripled the miles of tracks it had in 1840.
Oc. In 1860 the amount of tracks in both the North and the South had not increased
Od. In all three decades, the North had more miles of tracks than the South

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:

the hollywood film industry of 1950 was threatened on several different fronts. television broadcasting was rapidly becoming the dominant entertainment medium in the united states. the paramount anti-trust consent decree requiring separate ownership for production companies and theater chains had gone into effect on 1 january 1950. large numbers of young men and women were marrying, having children, and moving to the suburbs, which affected the viability of downtown first-run movie theaters. foreign revenues were endangered by protectionist tactics including quota systems, high taxes, and blocked funds. finally, the morality and patriotism of hollywood films and filmmakers were under attack from government, religious, and citizens' groups.

explanation: