Senate is a type of Legislature. Senate is related to Congress. Congress is related to Branch. Branch is related to Reach. 
Composition is a type of Essay. Essay is the opposite of Hypothesis. Hypothesis is a synonym of Possibility. Possibility is related to Opportunity. 
Legislature <--IsA-- Senate <--RelatedTo--> Congress <--RelatedTo--> Branch <--RelatedTo--> Reach 
Composition --IsA--> Essay <--Antonym--> Hypothesis <--Synonym--> Possibility <--RelatedTo--> Opportunity 