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: moss causes chemical weathering. 
Sentence2: If the moss was completely dried then it is dead.
[EX A]: moss

[EX Q]: Sentence1: a battery converts chemical energy into electrical energy. 
Sentence2: Battery electricity comes conversion.
[EX A]: battery

[EX Q]: Sentence1: a switch is used to start the flow of current in an electrical circuit. 
Sentence2: Each switch is moved up for on, and down for off.
[EX A]:
switch