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: when a river floods , that river deposits soil in flood plains. 
Sentence2: Hurricanes can cause local flooding, flash flooding, or coastal flooding.

Answer: flood


Question: Sentence1: Fertilization of gametes produces a diploid zygote. 
Sentence2: After fertilization of gametes it undergoes cell division to become an embryo.

Answer:
Fertilization