Cotton is related to Soft. Soft is the opposite of Solid. Rubber is a type of Solid. 
Cluster is related to Group. Group is related to Colony. Colony is related to New. New is related to Innovative. 
Cotton <--RelatedTo--> Soft <--Antonym--> Solid <--IsA-- Rubber 
Cluster <--RelatedTo--> Group <--RelatedTo--> Colony <--RelatedTo--> New <--RelatedTo--> Innovative 