It was 'The Great Migration.'
"The Great Migration<span> was the movement of 6 million African-Americans out of the rural Southern United States to the urban Northeast, Midwest, and West that occurred between 1910 and 1970."</span>
The thing which was a major factor that threatened the major unity in the United States in the mid-19th century was:
<h3>The Great Depression</h3>
This refers to the period around 1929 in the United States which has a profound effect on the national economy.
This led to the failure of many banks, increase in unemployment and high deflation rates which all threatened the national unity.
Read more about Great Depression here:
brainly.com/question/441267
I'm not sure if you meant in this way, but the government is divided into 3 branches-judicial, executive, and legislative. Let me know if you need anything else!! :)
I did some research and the lowest range was 1,000,000 and the highest was 1,700,000. Its hard to estimate this because they didnt have the proper recording instruments we have today.
