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: if an object is black then that object absorbs all visible light. 
Sentence2: Something is black if it absorbs visible light and doesn't reflect.

A: light
****
Q: Sentence1: Results can be damaging or disastrous. 
Sentence2: Lack of immunization can be damaging or disastrous.

A: damaging
****
Q: Sentence1: Intelligence has survival value. 
Sentence2: birds have a high survival value.

A:
survival
****