Hand is related to Rub. Rub is related to Slide. Slide is related to Tall. 
Brain is related to Thinking. Thinking is related to Certain. Certain is the opposite of Uncertain. 
Hand <--RelatedTo--> Rub <--RelatedTo--> Slide <--RelatedTo--> Tall 
Brain <--RelatedTo--> Thinking <--RelatedTo--> Certain <--Antonym--> Uncertain 