Level is related to Class. Class is a synonym of Distribute. Distribute is a type of Spread. Invasion is a type of Spread. 
Shelter is a synonym of Protection. Patrol is a type of Protection. 
Level <--RelatedTo--> Class <--Synonym--> Distribute --IsA--> Spread <--IsA-- Invasion 
Shelter <--Synonym--> Protection <--IsA-- Patrol 