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: Cnidarians are invertebrates such as jellyfish and corals. 
Sentence2: Jellyfish and corals are radial, tentacled animals that live mostly in the seas.

Answer: corals


Question: Sentence1: Leeches are external parasites. 
Sentence2: Leeches live on the surface of their hosts.

Answer: Leeches


Question: Sentence1: operating an automobile usually requires fossil fuels. 
Sentence2: Fossil fuel burning in automobiles, factories, and power plants also add aerosols to the atmosphere while polluting clouds (Figure 4).

Answer:
automobile