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: Telephone Telephone calls are expensive. 
Sentence2: Communicating by transmitting sound is expensive.

Answer: expensive


Question: Sentence1: Sand and mud are examples of sediments. 
Sentence2: layers of sand over the remains of organisms over time can create fossils.

Answer: Sand


Question: Sentence1: an automobile engine transforms chemical energy into mechanical energy. 
Sentence2: An automobile changes chemical energy into motion.

Answer:
automobile