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.

Sentence1: Fractures heal when osteoclasts form new bone. 
Sentence2: Fractures A fracture is a broken or cracked bone.
Fractures

Sentence1: infection can cause bodily tissues to swell. 
Sentence2: Bacteria can cause bodily tissues to swell.
bodily

Sentence1: a greenhouse is used to protect plants by keeping them warm. 
Sentence2: If the weather is warm, their temperature rises.

warm