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: an animal requires nutrients to grow and heal. 
Sentence2: Microbes can help an animal to grow and heal.

Answer: grow


Question: Sentence1: electric devices require electrical energy to function. 
Sentence2: Lie detectors are electrical or mechanical devices.

Answer: devices


Question: Sentence1: Sponges are a source of food for many species of fish. 
Sentence2: organisms attached to the ocean floor are a source of food for many species of fish.

Answer:
fish