Final answer:
A trader with a long position in gold futures is anticipating that the price of gold will increase to make a profit. This is conceptually similar to portfolio investors in the foreign exchange market who buy or sell currencies based on expectations of future value changes.
Step-by-step explanation:
A trader who has a long position in gold futures wants the price of gold to increase in the future. This is similar to how expectations about future exchange rates can influence demand and supply in foreign exchange markets. A long position means the trader has agreed to purchase the asset, in this case, gold, at a set price in the future, with the belief that its price will rise. An increase in the price of gold would thus result in a profit when the future contract is executed. Likewise, expectations of a currency's future value can drive its demand and supply in foreign exchange markets, with investors demanding a currency if they believe its value will go up, and supplying a currency - or selling it - if they believe its value will go down.