The german use of build public support for america's entry into world war i.

 submarine attacks

Context/detail:

Public outrage in the US against the Germans swept the nation following the sinking of the British ocean liner, Lusitania.  When a German U-boat (submarine) sank the Lusitania in May, 1915, over 1,000 persons were killed, including more than 100 Americans. The passenger liner was targeted by the Germans because they suspected weapons were being shipped to Britain in the cargo hold of the ship.

Germany managed to stave off American entry into the war at the time by pledging to stop submarine attacks.  But a couple years later they resumed such attacks, and there was also an intercepted telegram that showed Germany was trying to secure Mexico as an ally against the United States.  In 1917, the US declared war on Germany in response.

trade

explanation:

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.