Nthe 1800s, both “old” and “new” immigrants to the united states faced hostility because of limited housing availability worries about overpopulation. high us unemployment levels. differences in culture and language.

Differences in culture and language.

Explanation:

Immigrants in the United States faced social tensions in the 1800s because they were regularly stereotyped and discriminated. They suffered violence because they were perceived as different. Despite the social tension, immigrants brought a new vitality to the US. They helped transform the American culture, showing that diversity and unity are the main sources of national strength.

a

"the land of the dead"

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.