Learning can be used for Preparation. Learning is related to Know. 
Brown is related to Cake. Cake is related to Ice. Ice is a type of Solid. Solid is related to Waste. 
Preparation <--UsedFor-- Learning <--RelatedTo--> Know 
Brown <--RelatedTo--> Cake <--RelatedTo--> Ice --IsA--> Solid <--RelatedTo--> Waste 