Exploring the Foreign Exchange Market (Курс)

Domestic Currency vs. Foreign Currency
What is meant by Domestic Currency?
What is the meaning of Foreign currency?
If a person relocates from his own country to another country, then what would be the domestic currency in the new country?
In which currency foreign trade happens?
The trade agreement between two countries may encourage the use of exporter’s domestic currency in case of export or import. Whether it is binding for the businesses to pay for imports in exporter’s domestic currency?

What is meant by foreign exchange market?
Majority of the foreign exchange buying and selling nowadays happens online or offline? Comment.
For how many days forex market operates in a week?
Who are the participants in a foreign exchange market?
Currencies are trade singly or in pairs in forex market?
The transactions in the foreign exchange market are confined to a few foreign currencies. Comment.
Which are the most frequently traded currencies in the forex market?

Is there a central building or exchange where forex trading happens?
On which days we often see relatively higher trading volume in the forex market compared to other weekdays?
Whether major financial centers like London, New York, Tokyo and Hongkong represents the entire forex market?

How do spot and forward markets differ in the forex trading?
What is meant by T+2 settlement in spot market?
Whether spot market transactions are based on current market price or mutually agree price of the currencies being exchanged? Comment.
Majority of the forex transactions occur in the spot market or forward market. Comment.
Whether delivery of the currencies takes place immediately in forward market?
Whether most transactions in forward market have delivery time frame of 1-3 months or 3-6 months?