Final answer:
Exports and imports of gold, foreign exchange changes, and liabilities to foreign central banks affect a country's trade balance and foreign exchange reserves.
Step-by-step explanation:
Exports and imports of gold, increases, and decreases of foreign exchange, and liabilities to foreign central banks are all factors that affect a country's balance of trade and its foreign exchange reserves. They are important components of international finance and trade. For example, when a country exports gold, it increases its foreign exchange reserves, and when it imports gold, it decreases them. Similarly, when a country has more liabilities to foreign central banks, it reduces its foreign exchange reserves, and when it has fewer liabilities, it increases them.