Need help with these two questions please

1. Discuss the implications of an increase in default risk on corporate bonds on the demand on these bonds and on the demand for default-free bonds? Please use a graph to demonstrate your answer. 2. The interest rate on municipal bonds falls relative to the interest rate on Treasury securities when (a)corporate bonds become less risky. (b) income tax rates increase. (c) there is a major default in the municipal bond market. (d) municipal bonds become less widely traded. (e) none of the above occur