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.

Sentence1: Antigens are proteins foreign to the body. 
Sentence2: antigens are proteins.
proteins

Sentence1: if an object is kicked then force is exerted on that object. 
Sentence2: if an object is kicked then a measurement of newtons is exerted on that object.
exerted

Sentence1: Foods usually were covered with copious quantities of salt or saturated salt brine, and the salt was allowed to infuse into the tissue while dehydrating the product. 
Sentence2: Salting food preserves it.

Foods