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: healing requires rest. 
Sentence2: Healing and cell regeneration follows.
[A]: healing


[Q]: Sentence1: Distance is measured in meters the SI unit of distance. 
Sentence2: The SI unit of distance is in meters.
[A]: SI


[Q]: Sentence1: Plants represent the first trophic level. 
Sentence2: Energy is passed up a food chain from plants.
[A]:
Plants