Yield is a synonym of Income. Income is related to Profit. 
Stretch is a type of Extension. Stretch is related to Workout. Workout is a synonym of Practice. Practice is a type of Use. 
Yield <--Synonym--> Income <--RelatedTo--> Profit 
Extension <--IsA-- Stretch <--RelatedTo--> Workout <--Synonym--> Practice --IsA--> Use 