Why didm the us join world war 1?

Which of the following terms best describes the period of the 1920s? What was the name of the town on the south branch Potomac river taken over by both unoin and confederate troops at least 50 different times during the civil war? What invention led to an increasein numbers of slaves who worked on plantations? How much is a 1936 series e dollar bill worth with part of the front of the bill printed on the back? Who established the Goodnight-Loving Trail? Why is the flag so much shorter today than it was when Mary Pickersgill sewed it? What is the value of a 1943 zinc penny? Why were slaves forts located where they were? What did the Native American word Missouri mean? What was the Santa Fe trial? Are 1919 pennies rare? Was the United States part of the allies in World War 1? Which city did Lewis and clark start their journey? What is the value of 1947 S mint penny? How did the north keep the south from trading there cotton to other countries during the civil war? Why the north and the south fought? What impact did Abraham Lincoln have on todays society? What was an unintended consequence of Hernando desoto's expedition? What battle was not fought in the western theater? The Indian warrior who led the massacre of 1622 against the Virginia settlers was?