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: plant requires seed dispersal for reproduction. 
Sentence2: plants are pollinated by birds.

A: plant
****
Q: Sentence1: Corals Corals are in the polyp stage. 
Sentence2: Something in the polyp stage can form large colonies in shallow tropical water.

A:
polyp
****