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 switch is used to start the flow of current in an electrical circuit. 
Sentence2: lights are on when there is flow of current in an electrical circuit.
[A]: circuit


[Q]: Sentence1: Flowers produce seeds for reproduction. 
Sentence2: flowers require dispersal for reproduction.
[A]: Flowers


[Q]: Sentence1: Influenza is a disease caused by viruses. 
Sentence2: Populations of the cause of influenza do not grow through cell division because they are not cells.
[A]:
Influenza