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: Protein Protein is needed for tissue maintenance and repair. 
Sentence2: protein repairs cells.
[A]: Protein


[Q]: Sentence1: wind is used for producing electricity. 
Sentence2: Wind is caused because of pressure differences in the atmosphere.
[A]: wind


[Q]: Sentence1: Some mollusks are nearly microscopic. 
Sentence2: An abalone is a shellfish or mollusk.
[A]:
mollusks