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: Soil Erosion Soil erosion is a natural process. 
Sentence2: wind and rain is a natural process.

Answer: natural


Question: Sentence1: Water erosion has similar consequences as wind erosion. 
Sentence2: exposure to water can cause erosion.

Answer: Water


Question: Sentence1: ice wedging is when ice causes rocks to crack by expanding in openings. 
Sentence2: Freezing water expands cracking and breaking the rocks.

Answer:
crack