Key is related to Door. you are likely to find Door in/at/on Bus. 
Giant is related to Ocean. you are likely to find Shell in/at/on Ocean. Shell is related to Station. King is a type of Station. 
Key <--RelatedTo--> Door --AtLocation--> Bus 
Giant <--RelatedTo--> Ocean <--AtLocation-- Shell <--RelatedTo--> Station <--IsA-- King 