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: a battery converts chemical energy into electrical energy. 
Sentence2: A battery produces a flow of electrons.
[A]: battery


[Q]: Sentence1: Refrigerators are major users of electricity. 
Sentence2: Keeping food fresh for a long period of time requires a lot of electricity.
[A]: electricity


[Q]: Sentence1: seed dispersal has a positive impact on a plant. 
Sentence2: Seed dispersal has a positive impact on flowering and yield.
[A]:
dispersal