Time is related to Heat. Heat is related to Burn. Burn is related to Bridge. Bridge is related to Troubled. 
Background is a synonym of History. Biography is a type of History. Profile is a type of Biography. Profile is a different concept from Front. 
Time <--RelatedTo--> Heat <--RelatedTo--> Burn <--RelatedTo--> Bridge <--RelatedTo--> Troubled 
Background <--Synonym--> History <--IsA-- Biography <--IsA-- Profile <--DistinctFrom--> Front 