Why/how did the Treaty of Brest-litovsk end Russian involvement in World War 1?

What three political groups came out of the french revolution?

What do most climatologists see as a major cause of rising global temperatures? a. earth's closer proximity to the sun due to its gravitational pull b. greenhouse gases produced by burning fossil fuels c. rising ocean levels caused by melting polar ice sheets d. water pollution cause by industrial waste

Were african-americans allowed to serve in the military in wwi? explain