Which factor contributed most to the rise of inner-city overcrowding in the late nineteenth century?

People from all over the world were immigrating abroad in search for better work and social conditions.

Explanation:

The United States was the fastest growing economy in the World, thus many factories and businesses were hiring more and more people. In addition, people living in rural areas inside the US were also moving in to the cities or the suburbs. Soon, however the cities were overcrowding and along with it came problems such as traffic, noise, pollution and a need for better infrastructure and health systems. Immigrants coming from all over the world began to settle in neighborhoods and it gave birth to communities inside the big cities that kept the traditions and customs of their countries of origin. We can find most them even in the modern era.

ummm? is that supposed to be a question or a but this is a reason he won re-election

explanation:

"despite progress in the war, lincoln and most political pundits were convinced that he would lose his bid for reelection in 1864. the country was war weary and the democratic party's nominee, george mcclellan, was likely to negotiate a peace treaty with the confederacy if elected." - loc.gov

i am not 100% positive but i think it is is b. both are non-partisan jobs

i am pretty sure that members of congress have term limits, can be impeached, and are nominated through direct popular vote.