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: decomposition increases the amount of nutrients in the soil. 
Sentence2: decomposition increases the amount of cations.

A: amount
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Q: Sentence1: boiling means change from a liquid into a gas by adding heat energy. 
Sentence2: boiling changes a liquid into steam.

A: liquid
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Q: Sentence1: gravity pulls objects towards planets. 
Sentence2: Gaia is our planet Earth.

A:
planets
****