What happened in russia in 1917 that led the united states to justify its involvement in world war i as a fight for democracy? russia signed a military defense treaty with france and great britain. russia signed the treaty of brest-litovsk and made peace with the germans. russian revolutionaries overthrew the czar and established a provisional government. russian bolsheviks, under vladimir lenin's leadership, toppled the provisional government.

"Russian Bolsheviks, under Vladimir Lenin's leadership, toppled the provisional government" is what led the United States to justify its involvement in World War I as a fight for democracy, since the Bolsheviks were communist. 

The constant presence of diseases or infectious agents within a given geographic area or population group. it may also refer to the usual prevalence of a given disease with such area or group. it includes holoendemic and hyperendemic diseases. a holoendemic disease is one for which a high prevalent level of infection begins early in life and affects most of the child population, leading to a state of equilibrium such that the adult population shows evidence of the disease much less commonly than do children (malaria in many communities is a holoendemic disease). a hyperendemic disease is one that is constantly present at a high incidence and/or prevalence rate and affects all groups equally. so probably family history.

They showed the country that integration could be successful.