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: if an object is made of a material then that object has the properties of that material. 
Sentence2: If an object is made of a drug, then that object has the properties of that drug.
[EX A]: made

[EX Q]: Sentence1: knowledge of the stars can be used to navigate. 
Sentence2: Knowledge of the stars can be used to travel.
[EX A]:
be