I think question 8 is 1, not 100% sure though...
Economic failures and years of warfare, the Chernobyl disaster, perestroika glasnost and Mikhail Gorbachev all of these factors contributed to the collapse of the Soviet Union or USSR in the year 1991. Some of these incidents had a direct impact on the breaking of USSR into several countries, while others had a direct role.
The use of non-renewable resources such as coal which was cheaper, which was used to mine iron
