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: Enveloped viruses make their own membranes. 
Sentence2: Some viruses make their own membranes.

Answer: make


Question: Sentence1: Water is essential for all life on Earth. 
Sentence2: H2O is needed for all life on Eartth.

Answer: Earth


Question: Sentence1: Specialization occurs when competing species evolve different adaptations. 
Sentence2: Beak variation came about because of competing species evolving different adaptations.

Answer:
adaptations