Power is related to Gas. Gas can Explode. Explode is a type of Condemn. 
Source is related to Tree. Tray is etymologically related to Tree. Tray is related to Serving. 
Power <--RelatedTo--> Gas --CapableOf--> Explode --IsA--> Condemn 
Source <--RelatedTo--> Tree <--EtymologicallyRelatedTo-- Tray <--RelatedTo--> Serving 