Pizza is a type of Food. Food is related to Market. Market is related to Commercial. 
Lift is related to Slope. Slope is related to Physics. Physics is related to Gravity. 
Pizza --IsA--> Food <--RelatedTo--> Market <--RelatedTo--> Commercial 
Lift <--RelatedTo--> Slope <--RelatedTo--> Physics <--RelatedTo--> Gravity 