What term was used to describe the rough ride between free and slave states by the mid 1800s

The answer is:  Mason-Dixon Line

Mason-Dixon Line marked the northern limit where slavery was still allowed in united states (if you move one stop north from the mason-dixon line, you could be in jail if you owned a slave).

The line has not been moved for around 150 years before eventually the missouri compromise was made and reduce the area where slavery was still allowed.

answer; (d) i believe that the correct answer is americans finally ran out of ammunition;

no

explanation:

not everyone in america is free. it is has always been a unequal society. and yet people come in swarms, in search of better lives. some are brought as children, unaware, unknowing. some arrive and just don’t leave. they build lives, pay taxes, raise families. some enter illegally, fleeing persecution in their home country.

there are many reasons why human beings are so attracted to america, despite its history of bitterness towards immigrants.

there are almost two million immigrants brought to the us when they were children. president donald trump and his collaborators are determined to rid the us of as many undocumented immigrants as they can, and stop others from coming because none of their ancestors were immigrants.

america has so many things and yet it lacks the one thing that humanity needs to fully thrive. and so this country will not be at peace in itself until it resolves the pain at the heart of slavery, attacking immigrants, and crumble the rights of those with less power.