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: People of all ages and activity levels perspire or sweat. 
Sentence2: Perspiration reduces body heat.
answer:
perspire


question:
Sentence1: threatening behavior by predators causes a porcupine to extend its quills. 
Sentence2: Fishers are one of the few specialized predators on porcupines.
answer:
predators


question:
Sentence1: plant requires seed dispersal for reproduction. 
Sentence2: Seeds are dispersed by animals.
answer:

dispersal