Which of the following was a problem that many urban americans faced during the early 1900s?

a. tensions between abolitionists and slave owners
b. a lack of unskilled workers for factory jobs
c. fear of attack by hostile native americans
d. crowded, unsanitary living conditions in tenements

The correct answer is D) Crowded, unsanitary living conditions in tenements.  

A problem many urban American faced during the early 1900s was Crowded, unsanitary living conditions in tenements.  

Many Americans migrated to from poor rural areas in the United States to larger, urban cities. By 1790, 90% of Americans lived in rural areas. But urbanization increased in the early 1800s in the United States. By 1890, 30% of citizens lived in urban areas. One of the problems that many urban American faced during the early 1900s was Crowded, unsanitary living conditions in tenements. The Industrial Revolution of the late 1790s and early 1800s attracted many people to work in the factories located in the cities.  

genetics is the study of how dna works, the methodologies defining the new recent technologies allow scientist to have a panoramic view of the entire dna landscape, especially how genomes interact with their environment, including off course, factors outside their organisms.

thus is very possible the existence of both scenarios, where populations of isolated individuals have different genetic traits, and share traits related to genetic mutation, due rats can easily travel overseas using human transport channels. so scientists could get a vast number of data, including human interaction, evolution of rodents, health development, spread of infections, development of new organisms, how genomes evolve in different environments and so on.

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