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.

[EX Q]: Sentence1: Parasites are organisms that live off a host. 
Sentence2: roundworms may be free-living or live off a host.
[EX A]: host

[EX Q]: Sentence1: Heterotrophs are living things that cannot make their own food. 
Sentence2: food contains organic molecules.
[EX A]: food

[EX Q]: Sentence1: matter vibrating can cause sound. 
Sentence2: When the waves pass our ears, a sound is detected.
[EX A]:
sound