instruction:
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.
question:
Sentence1: Coral reefs are made up of the accumulated exoskeletons of the coral polyp. 
Sentence2: coral polyps form reefs.
answer:
polyp


question:
Sentence1: Some birds are pollinators that co-evolved with plants. 
Sentence2: insects pollinate plants.
answer:
plants


question:
Sentence1: when a plant grows , the size of the leaves of that plant may increase. 
Sentence2: when a perennial grows, the size of its leaves may increase.
answer:

grows