Mercatura
Commodities are a geography problem: everything is produced where it isn't consumed. Three ways to test yourself - click the right spot on the map.
Given a commodity, click the top producing / exporting countries. When there are several giants, you must find all of them.
The ~9 straits and canals where seaborne trade - and price risk - actually lives. Click the location on the map.
Origin is highlighted. Click where the cargo first ships to - a country, or a whole region for hub-processed goods (cocoa, LNG). Find every big corridor.
The terminals the trade funnels through. Given a port and its claim to fame, click where it sits - one shot, graded on how close you land.
A shuffled mix of all three modes. The full commodity-geography workout.