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.

[EX Q]: Sentence1: a light bulb is used for seeing in the dark. 
Sentence2: light is required for seeing.
[EX A]: seeing

[EX Q]: Sentence1: healing requires rest. 
Sentence2: Healing and cell regeneration follows.
[EX A]: healing

[EX Q]: Sentence1: Adult sponges are sessile. 
Sentence2: Adult sponges have polyps.
[EX A]:
Adult