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: the mass of an object causes the gravitational force exerted by that object. 
Sentence2: gravitational force accelerates objects.
[A]: force


[Q]: Sentence1: a flashlight converts chemical energy into light energy. 
Sentence2: Only as long as there are batteries in the flashlight, the flashlight will function.
[A]: flashlight


[Q]: Sentence1: Genetic diversity is really a form of biodiversity. 
Sentence2: cross-pollination increases biodiversity.
[A]:
biodiversity