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: Autumn brings the changing of the seasons. 
Sentence2: Earth 's tilt on its rotating axis causes autumn.

Answer: Autumn


Question: Sentence1: adding salt to a solid decreases the freezing point of that solid. 
Sentence2: Water density decreases with temperature and increases with salt content.

Answer: decreases


Question: Sentence1: Hatching is a prerequisite for embryo implantation in the uterus. 
Sentence2: Embryo implantation is used in reproduction.

Answer:
embryo