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: boiling means change from a liquid into a gas by adding heat energy. 
Sentence2: boiling changes a liquid into steam.
[A]: liquid


[Q]: Sentence1: protein is used to repair cells by the human body. 
Sentence2: Wound healing requires protein.
[A]: protein


[Q]: Sentence1: Once startled, the animal runs away often taking short leaps and emitting low cries. 
Sentence2: Loud noises can cause animals to run away.
[A]:
away