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: ultraviolet light causes sunburn. 
Sentence2: Sunburn risk is higher at elevation.

Answer: sunburn


Question: Sentence1: Algae have varied life cycles. 
Sentence2: And fish eat algae.

Answer: Algae


Question: Sentence1: a glacier causes mechanical weathering. 
Sentence2: Mechanical weathering creates sediment that is transported via wind, water, and ice.

Answer:
mechanical