Head is related to Use. Use is related to Fly. 
Classroom can be used for Teach. Teach is a type of Inform. Testify is a type of Inform. Testify is a synonym of Prove. 
Head <--RelatedTo--> Use <--RelatedTo--> Fly 
Classroom --UsedFor--> Teach --IsA--> Inform <--IsA-- Testify <--Synonym--> Prove 