Excuse is a type of Justify. Excuse is related to School. School is related to Punishment. Punishment is related to Book. 
Law is related to Degree. Degree is related to Achievement. Achievement is derived from Achieve. 
Justify <--IsA-- Excuse <--RelatedTo--> School <--RelatedTo--> Punishment <--RelatedTo--> Book 
Law <--RelatedTo--> Degree <--RelatedTo--> Achievement --DerivedFrom--> Achieve 