The Dust Bowl, also known as the Dirty Thirties, was a period of severe dust storms that greatly damaged the ecology and agriculture of the US and Canadian prairies during the 1930s; severe drought and a failure to apply dryland farming methods to prevent wind erosion (the Aeolian processes) caused the phenomenon.
The main reason why OPEC imposed an oil embargo on the US is because the US supported Israel in its “Yom Kippur War” with Egypt, and OPEC was made up of states that were against Israel, who was fighting the war against Egypt.
The name given to Gorbachev's policy of political openness was called "glasnost." This usually meant a sort of openness or transparency for politics, such as that the press and the public could attend court hearings and that the sentence would be read out in public.
It is important because the French regained the high ground