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.

Q: Sentence1: if an object is made of a material then that object has the properties of that material. 
Sentence2: If an object is made of a drug, then that object has the properties of that drug.

A: made
****
Q: Sentence1: riding a bike does not cause pollution. 
Sentence2: riding a bike does not release particles.

A: bike
****
Q: Sentence1: a light bulb requires electrical energy to produce light. 
Sentence2: A bulb requires electrical energy to produce electromagnetic radiation.

A:
bulb
****