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: Fractures heal when osteoclasts form new bone. 
Sentence2: Fractures A fracture is a broken or cracked bone.
answer:
Fractures


question:
Sentence1: Mammalian teeth are important for digestion. 
Sentence2: bats' teeth are important for digestion.
answer:
digestion


question:
Sentence1: Mammals generate heat mainly by keeping their metabolic rate high. 
Sentence2: food keeps mammals' metabolic rates high.
answer:

Mammals