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: Echinoderms use pheromones to communicate with each other. 
Sentence2: Echinoderms are known for their round symmetry.

Answer: Echinoderms


Question: Sentence1: To keep cut flowers lasting longer, use a commercial florist preservative such as Floralife. 
Sentence2: Dehydrating food is used to make it last longer.

Answer: lasting


Question: Sentence1: Nature of Light Light is a form of energy. 
Sentence2: If an object is black then that object absorbs all visible energy.

Answer:
energy