Why did many immigrants come to the United States from Germany in the mid-1840's?

Explanation:

In the decade from 1845 to 1855, more than a million Germans fled to the United States to escape economic hardship. They also sought to escape the political unrest caused by riots, rebellion and eventually a revolution in 1848.

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:

wisdom

explanation:

the fact that that the teachings on the cosmic order comes from, or through, the heart center