Vulnerable is related to Dangerous. Dangerous is related to Fire. Fire is a type of Criticism. 
Type is related to Main. Main is related to Important. Important is derived from Import. 
Vulnerable <--RelatedTo--> Dangerous <--RelatedTo--> Fire --IsA--> Criticism 
Type <--RelatedTo--> Main <--RelatedTo--> Important --DerivedFrom--> Import 