Tank is related to Supply. Supply is related to Economic. Economic is related to Trade. 
Nerve is related to Cell. Cell is related to Stream. Stream is a synonym of Series. Series is a synonym of Line. 
Tank <--RelatedTo--> Supply <--RelatedTo--> Economic <--RelatedTo--> Trade 
Nerve <--RelatedTo--> Cell <--RelatedTo--> Stream <--Synonym--> Series <--Synonym--> Line 