<h2>b. It helped convince U.S. leaders to send american troops to fight in Europe.</h2>
Context/detail:
Public outrage in the US against the Germans had swept the nation a couple years earlier, following the sinking of the British ocean liner, Lusitania. A German U-boat (submarine) sank the Lusitania in May, 1915. Over 1,000 persons were killed, including more than 100 Americans.
Germany managed to stave off American entry into the war at that time by pledging to stop submarine attacks. But a couple years later they resumed such attacks. That was one factor that helped to convince the USA to enter the war. Then also there was the intercepted telegram (the "Zimmerman Telegram") that showed Germany was trying to secure Mexico as an ally against the United States. In April, 1917, the US declared war on Germany in response.
The earliest large cities in colonial North America were located on the northeastern coast. These cities include Boston, New York City and Philadelphia.
