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: wiring requires an electrical conductor. 
Sentence2: Gold is an excellent conductor of electricity.
conductor

Sentence1: Hydrogen bonds cause water to expand when it freezes. 
Sentence2: Water freezes into ice when cooled.

freezes