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: a camera is used for recording images. 
Sentence2: a camera is used for recording binary.

Answer: camera


Question: Sentence1: an animal requires air for survival. 
Sentence2: It is breathed in by animals and restored to the air by the photosynthesis mechanism of plants.

Answer: air


Question: Sentence1: some light bulbs convert electricity into light and heat energy. 
Sentence2: Heat energy is the amount of energy in a substance.

Answer:
heat