Primary is related to Election. Election is derived from Elect. Elect is related to Voting. Voting is related to Ballot. 
Plea is related to Prayer. Prayer is derived from Pray. Pray is related to Action. Arrival is a type of Action. 
Primary <--RelatedTo--> Election --DerivedFrom--> Elect <--RelatedTo--> Voting <--RelatedTo--> Ballot 
Plea <--RelatedTo--> Prayer --DerivedFrom--> Pray <--RelatedTo--> Action <--IsA-- Arrival 