Eye is related to Biological. Biological is related to Grow. Grow is related to Farmer. 
Price is related to Product. Product is related to Cake. Cake can be used for Serving. Serving is related to Piece. 
Eye <--RelatedTo--> Biological <--RelatedTo--> Grow <--RelatedTo--> Farmer 
Price <--RelatedTo--> Product <--RelatedTo--> Cake --UsedFor--> Serving <--RelatedTo--> Piece 