Cash Rate Cuts: Central Banks' Recession Combat Strategy - Efficacy Examined

The following question has to be addressed:
1. What was the main cause of the Global Financial Crisis (GFC) and why it has spread internationally? Do you believe that it could have been prevented?
Choose two of the following questions:  
2. One of the tools Australia and many other countries have used to fight the recession trends was to cut cash rates. The Reserve Bank of Australia has itself cut the cash rate from 6.75% in January 2008 to 2% in January 2016. Why do you believe central banks all over the world are using this tool to fight the recession in their economies? Do you believe it has been efficient in Australia and globally?