What are some of the reasons central banks and treasuries enter the foreign exchange markets,and in what important ways are they different from other foreign exchange participants?

The Foreign Exchange Market

What are some of the reasons central banks and treasuries enter the foreign exchange markets,and in what important ways are they different from other foreign exchange participants?

What are the four currencies that constitute about 80% of all foreign exchange trading?

Answers all questions and give short explanation. Reference the PowerPoint attached Questions are at the end of PowerPoints. You do not have to add question to the paper.