How did alliances between european nations trigger a chain reaction that led to world war 1?

Alliances roped those allies into the conflict.

Explanation:

After an ally came to help a country, the opposing side also called on their allies for assistance, this is how major players such as Germany and Britain were brought into a conflict originally started between the smaller countries

abraham lincoln  (february 12, 1809  – april 15, 1865) was an american statesman, politician, and lawyer who served as the 16th  president of the united states  from 1861 until  his assassination  in april 1865. lincoln led the nation through the  american civil war, its bloodiest war and its greatest moral, constitutional, and political crisis.[2][3]  he preserved the  union,  abolished slavery, strengthened the  federal government, and modernized  the u.s. economy.

the assassination of president lincoln was just one part of a larger plot to decapitate the federal government of the u.s. after the civil war. the first reaction to lincoln’s death was disbelief. then it quickly changed to grief. abraham lincoln’s death created an outpouring of grief from citizens in both the north and the south.

explanation:

lincoln was the first u.s. president to be assassinated. president abraham lincoln, america’s civil war leader, was assassinated just five days after confederate general robert e. lee surrendered his army at appomattox court house, ending the four-year war between the states. on the evening of april 14, 1865, lincoln was attending a performance of our american cousin at ford’s theatre in washington, d.c. john wilkes booth – a 26-year old actor, confederate sympathizer, and white supremacist – slipped into the presidential box and shot lincoln in the head. john wilkes booth and his conspirators had initially planned to kidnap lincoln to save the confederate states. but as the confederacy faltered, booth’s thoughts turned to murder. booth may have decided to act on his hatred after lincoln endorsed giving the right to vote to african-american men who had served in the union army.