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: Dinosaur bones, like many other artifacts, are fossilized. 
Sentence2: radioactive dating is used to determine the age of dinosaur bones.
answer:
Dinosaur


question:
Sentence1: Earthquakes are natural disasters. 
Sentence2: earthquakes can cause animals to leave an environment.
answer:
Earthquakes


question:
Sentence1: contact between rocks over long periods of time causes rocks to smooth. 
Sentence2: First, limestone is a strong rock.
answer:

rocks