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: Many plants respond to the days growing shorter in the fall by going dormant. 
Sentence2: Many plants respond to the autumnal equinox by going dormant.

A: Many
****
Q: Sentence1: when electricity flows to a light bulb , the light bulb will turn on. 
Sentence2: water pumps can turn on light bulbs.

A: bulb
****
Q: Sentence1: An ecosystem can be in a desert, a tropical jungle, an ocean or a pond. 
Sentence2: cutting down trees has a negative impact on a jungle.

A:
jungle
****