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: Nitrogen is found in proteins, nucleic acids, and chlorophyll. 
Sentence2: Nitrogen, as a gas, is colorless, odorless, and a generally inert element.
answer:
Nitrogen


question:
Sentence1: propulsion is used for flying by a spacecraft. 
Sentence2: Jets are used for flying by spacecraft.
answer:
flying


question:
Sentence1: Bound and free ribosomes are structurally identical and interchangeable. 
Sentence2: Bound and free structures are in the cytoplasm where proteins are made.
answer:

Bound