Justify is related to Explain. Explain is related to Understand. Master entails/necessarily involves Understand. 
Aids is related to Hear. Hear is related to Appear. Appear is related to Appearance. 
Justify <--RelatedTo--> Explain <--RelatedTo--> Understand <--Entails-- Master 
Aids <--RelatedTo--> Hear <--RelatedTo--> Appear <--RelatedTo--> Appearance 