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.

Q: Sentence1: lightning can cause a forest fire. 
Sentence2: Lightning can cause a natural cycle in forests.

A: lightning
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Q: Sentence1: Earthquakes cause massive damage. 
Sentence2: tectonic plates being pushed together causes massive damage.

A: damage
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Q: Sentence1: Mammals conserve body heat with their hair or fur. 
Sentence2: Foxes conserve body heat with their hair or fur.

A:
body
****