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: moss causes chemical weathering. 
Sentence2: Sphagnum moss mixed with peat moss.
answer:
moss


question:
Sentence1: cold fronts cause thunderstorms as they pass by. 
Sentence2: Thunderstorms create havoc.
answer:
thunderstorms


question:
Sentence1: breathing is when a gill converts from oxygen in water into oxygen in blood. 
Sentence2: Sharks use gills to breathe.
answer:

gill