Animal is related to Fish. Fish is related to Salt. Salt is related to Grain. Grain is related to Crop. 
Trap is a type of Hold. Pit can be used for Trap. 
Animal <--RelatedTo--> Fish <--RelatedTo--> Salt <--RelatedTo--> Grain <--RelatedTo--> Crop 
Hold <--IsA-- Trap <--UsedFor-- Pit 