food can be a source of an odor & smell is used for detecting odor ->  smell can be used to detect food odors  sense is a kind of characteristic of an animal & smell is a kind of sense ->  smell is a kind of characteristic of some animals  smell can be used to detect food odors & smell is a kind of characteristic of some animals ->  smell is used for finding food by some animals  smell is used for finding food by some animals & a fox is a kind of animal -> smell is used for finding food by foxes