Reason is the opposite of Random. Random is a synonym of Momentum. Momentum is related to Motion. Crawl is a type of Motion. 
Iron is related to Ingredient. Ingredient is related to Color. Color is related to Fair. Fair is related to Balanced. 
Reason <--Antonym--> Random <--Synonym--> Momentum <--RelatedTo--> Motion <--IsA-- Crawl 
Iron <--RelatedTo--> Ingredient <--RelatedTo--> Color <--RelatedTo--> Fair <--RelatedTo--> Balanced 