Specialize is a type of Change. Specialist is derived from Specialize. Specialist is related to Scientist. Scientist is etymologically related to Artist. 
Extension is related to Reach. Ground is a type of Reach. Ground is related to Average. Average is related to Math. 
Change <--IsA-- Specialize <--DerivedFrom-- Specialist <--RelatedTo--> Scientist --EtymologicallyRelatedTo--> Artist 
Extension <--RelatedTo--> Reach <--IsA-- Ground <--RelatedTo--> Average <--RelatedTo--> Math 