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: Thrinaxodon, a small Lystrosaurus Zone cynodont, shows many of the characters of the group. 
Sentence2: Thrinaxodon is from the animal family that eventually evolved into mammals.

A: Thrinaxodon
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Q: Sentence1: Chordates have a complete digestive system and a closed circulatory system. 
Sentence2: All chordates are vertebrates.

A: Chordates
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Q: Sentence1: Migration is a type of movement that changes population size. 
Sentence2: A life involving travel is a type of movement that changes population size.

A:
changes
****