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: Specialization decreases mortality 12,13 and increases survival. 
Sentence2: evolving different adaptations increases survival.

Answer: increases


Question: Sentence1: a sifter is used for separating mixtures. 
Sentence2: a sifter is used for some recipes.

Answer: sifter


Question: Sentence1: high mountains with well-rounded peaks can be formed by collision of crustal plates. 
Sentence2: high mountains with well-rounded peaks can be formed by collision of something studied by plate tectonics.

Answer:
collision