World war 1 brought increased immigration to the united states from which country

Immigration to the US during WWI led to an average of 1 million immigrants per year, since the US policy of "open door” immigration did not establish a limit on the number of people who could enter the country. Masses of immigrants who escaped the hardships of this long-lasting war came from European countries such as Italy, France, Germany, Britain and Russia. Besides, many refugees came from Bulgaria, Greece, Romania, Serbia, and Turkey, as well as Jews who fled for their lives from anti-Semitic feeling throughout eastern Europe. It is important to state that many immigrants enlisted in American military forces and served the US during the development of WWI.

your answer would be (a)

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.