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 is used to repair cells by the human body. 
Sentence2: Wound healing requires protein.

A: protein
****
Q: Sentence1: Climate refers to weather over a long period of time. 
Sentence2: weather is generally described in terms of temperature and moisture.

A: long
****
Q: Sentence1: Fish have a centralized nervous system with a brain. 
Sentence2: Fish include bass, crappie, and catfish.

A:
Fish
****