Given a category and a set of five words, find the word from the set that does not belong (i.e. is the least relevant) with the other words in the category. Words are separated by commas.
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Question: Category: nutritional value 
Words: iron, heavy, vitamin c, fat, brittleness

Answer: brittleness


Question: Category: elements 
Words: ban, fire, combustion, ground, flame

Answer: ban


Question: Category: animal 
Words: tiger, camp, cow, dog, fish

Answer:
camp