Obstacle is related to Eye. Eye is related to Fluid. Fluid is related to Soup. Soup is related to Common. 
Protest is the opposite of Concede. Concede is a type of Admit. Admit is related to Recognize. 
Obstacle <--RelatedTo--> Eye <--RelatedTo--> Fluid <--RelatedTo--> Soup <--RelatedTo--> Common 
Protest <--Antonym--> Concede --IsA--> Admit <--RelatedTo--> Recognize 