Generate an overlapping word between the given two sentences. When you find the overlapping words, they don't have to match exactly, e.g., "survival" and "survive" are valid overlapping words. Little words like "the" or "of" don't count! You must generate significant words which are not the stop words.

[Q]: Sentence1: smell is used for finding food by some animals. 
Sentence2: Food includes small rodents and birds.
[A]: food


[Q]: Sentence1: Among monogamous species of birds and mammals, both parents often care for their offspring. 
Sentence2: The period of parental care after birth for manogamous species are handled by both parents.
[A]: monogamous


[Q]: Sentence1: a rubber band snapping causes the particles in the rubber band to vibrate. 
Sentence2: After all, rubber bands tend to snap when stretched too thin.
[A]:
rubber