Bishop is a type of Weapon. Weapon is related to Arm. Arm is related to Inside. Inside is related to Balloon. 
Population can be used for Study. one thing you do when you Study is Learn. the last thing you do when you Learn is Practice. 
Bishop --IsA--> Weapon <--RelatedTo--> Arm <--RelatedTo--> Inside <--RelatedTo--> Balloon 
Population --UsedFor--> Study --HasSubevent--> Learn --HasLastSubevent--> Practice 