Brush is a type of Fight. Fight is related to Argue. Argue entails/necessarily involves Disagree. 
you are likely to find Pollution in/at/on Sky. Sky is etymologically related to Hide. Terrorism would make you want to Hide. 
Brush --IsA--> Fight <--RelatedTo--> Argue --Entails--> Disagree 
Pollution --AtLocation--> Sky --EtymologicallyRelatedTo--> Hide <--CausesDesire-- Terrorism 