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: Generally, pheromones are volatile substances. 
Sentence2: Male dogs use volatile substances in urine to mark their territory.

A: substances
****
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: poison causes harm to living things. 
Sentence2: Birds, like all living things, have intrinsic value.

A:
living
****