Corn is a different concept from Wheat. Wheat can be used for Cake. Cake is related to Angel. 
Cure is related to Medical. Medical is related to Disease. Virus can cause/lead to Disease. Aids is a type of Virus. 
Corn <--DistinctFrom--> Wheat --UsedFor--> Cake <--RelatedTo--> Angel 
Cure <--RelatedTo--> Medical <--RelatedTo--> Disease <--Causes-- Virus <--IsA-- Aids 