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: hunting requires seeing prey. 
Sentence2: hunting requires seeing an animal.

Answer: hunting


Question: Sentence1: when a gas in an open container evaporates , that gas spreads out into the air. 
Sentence2: when a gas in an open container evaporates gas molecules slamming into one another.

Answer: container


Question: Sentence1: Pregnancy is the carrying of one or more offspring from fertilization until birth. 
Sentence2: Pregnancy is another word for gestation.

Answer:
Pregnancy