accounting questions

please see attached. Original and quality work only. 

Name two reasons why overhead might be under-applied in a given year and how this might be able to be prevented? What is a predetermined overhead rate and how is it computed?  What do you feel is the best allocation base to use for the denominator in the predetermined overhead rate calculation and why?  What factors would you consider in choosing the allocation base?

Research the history of process costing in the United States. When did it begin to be used in manufacturing companies? What type of company would use a process costing system?

Investigate process costing accounting in at least one country outside of the United States. What are the reporting requirements, if any? If possible, find a company that would use process costing.