instruction:
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.
question:
Sentence1: protein is used to repair cells by the human body. 
Sentence2: Wound healing requires protein.
answer:
protein


question:
Sentence1: Sound vibrations travel at different speeds through different materials. 
Sentence2: the type of material through which sound passes changes the sound vibrations.
answer:
Sound


question:
Sentence1: if a planet becomes too hot then that planet cannot sustain life. 
Sentence2: Another name for Mars is the Red Planet.
answer:

planet