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
****
Q: Sentence1: zinc has a positive impact on the healing of wounds. 
Sentence2: oysters have a positive impact on the healing of wounds.

A: has
****
Q: Sentence1: Every member of every species needs to meet the challenges of survival and of reproduction. 
Sentence2: an animal must find a mate to ensure survival.

A:
survival
****