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.
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Question: Sentence1: if an object is made of a material then that object has the properties of that material. 
Sentence2: An object is an item in the real world.

Answer: object


Question: Sentence1: Fertilization occurs naturally in the fallopian tubes. 
Sentence2: fertilization is used for reproduction.

Answer: Fertilization


Question: Sentence1: hitting an object causes the particles in that object to vibrate. 
Sentence2: Ball is hit with bat by batter.

Answer:
hitting