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.

Sentence1: Results can be damaging or disastrous. 
Sentence2: Lack of immunization can be damaging or disastrous.
damaging

Sentence1: bacteria can cause people to become ill. 
Sentence2: bacteria can cause people to die.
bacteria

Sentence1: Baby birds have an egg tooth, which they use to peck out of the egg. 
Sentence2: baby birds have calcium carbonate shells.

Baby