Possession is a type of District. District is related to Civic. Civic is related to Duty. 
Delivery is a type of Act. Delivery is a type of Birth. Birth is related to Mother. Mother is a different concept from Dad. 
Possession --IsA--> District <--RelatedTo--> Civic <--RelatedTo--> Duty 
Act <--IsA-- Delivery --IsA--> Birth <--RelatedTo--> Mother <--DistinctFrom--> Dad 