Shell is a type of Emerge. Shell is related to Gasoline. Gasoline is related to Regular. 
Fuel is a type of Stimulate. you are likely to find Fuel in/at/on Plane. you are likely to find Alcohol in/at/on Plane. Alcohol is related to Port. 
Emerge <--IsA-- Shell <--RelatedTo--> Gasoline <--RelatedTo--> Regular 
Stimulate <--IsA-- Fuel --AtLocation--> Plane <--AtLocation-- Alcohol <--RelatedTo--> Port 