Which was a major argument in favor of the mexican war in 1846?

a.
northern abolitionists supported the war because mexico had refused to outlaw slavery.

b.
mexican forces had crossed the california border and killed hundreds of american civilians.

c.
mexico claimed u. s. territory in oregon and years of talks did not settle the issue.

d.
americans who believed in manifest destiny wanted to spread the american way of life.

the question is asking about the things that may have affected and what they effects had on the spanish conquest and settlement of america

explanation:

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: