Soften is a synonym of Yield. Yield is a synonym of Income. 
Burn is related to Bake. Bake is related to Bread. Bread is related to Beard. Beard is part of Face. 
Soften <--Synonym--> Yield <--Synonym--> Income 
Burn <--RelatedTo--> Bake <--RelatedTo--> Bread <--RelatedTo--> Beard --PartOf--> Face 