This timeline shows the leaders of the Soviet Union and when they ruled starting with Kerensky, the head of the Provisional Government, and ending with Gorbachev in 1991 when the Russian Republic was formed. http://www.rff.com/timeline_soviet.htm
Professor plum is showing the detached style of listening. This type of listener are intellectually not present in a conversation although they are present physically. In the situation described clearly the professor was not listening to what Roberto was saying.
I think . circular motions in the atmosphere.
fossil fuels make up the biggest percentage of air pollution
