Blue is a synonym of Adult. Adult is the opposite of Youth. Youth is the opposite of Age. Age is related to Hair. 
Tend is etymologically related to Attend. Attend is a synonym of See. 
Blue <--Synonym--> Adult <--Antonym--> Youth <--Antonym--> Age <--RelatedTo--> Hair 
Tend --EtymologicallyRelatedTo--> Attend <--Synonym--> See 