Breathe requires Alive. Alive is related to Human. Human is related to Earth. Earth is related to Stuff. 
Eating is related to Knife. you are likely to find Knife in/at/on Back. 
Breathe --HasPrerequisite--> Alive <--RelatedTo--> Human <--RelatedTo--> Earth <--RelatedTo--> Stuff 
Eating <--RelatedTo--> Knife --AtLocation--> Back 