Answer:Bolsheviks Executed Czar Nicholas II and his family
Explanation:
In Yekaterinburg, Russia, Czar Nicholas II and his family are executed by the Bolsheviks, bringing an end to the three-century-old Romanov dynasty. ... In March 1917, revolution broke out on the streets of Petrograd and Nicholas was forced to abdicate his throne later that month.
The election of President Abraham Lincoln was the final straw that caused the South to secede from the United States. Hope this helps! :)
I think a and d but I could be wrong
