Exhaust is a type of Gas. Gas is related to Burning. Burning is a form of Burn. Burn is related to Oven. 
Terrorist is a type of Human. Terrorist is a type of Radical. Radical is a type of Character. 
Exhaust --IsA--> Gas <--RelatedTo--> Burning --FormOf--> Burn <--RelatedTo--> Oven 
Human <--IsA-- Terrorist --IsA--> Radical --IsA--> Character 