Flow is related to Constant. Constant is a type of Quantity. Quantity is related to Time. 
Pizza is a type of Food. Pizza would make you want to Drink. Drink is part of Meal. 
Flow <--RelatedTo--> Constant --IsA--> Quantity <--RelatedTo--> Time 
Food <--IsA-- Pizza --CausesDesire--> Drink --PartOf--> Meal 