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: Interstellar space contains a plasma. 
Sentence2: interstellar space contains electrons, atoms, and stars.
answer:
Interstellar


question:
Sentence1: creating paper requires cutting down trees. 
Sentence2: Trees begin as epiphytes on host trees.
answer:
trees


question:
Sentence1: Mollusks have a simple heart, which pumps the blood throughout the body. 
Sentence2: Mollusks have hearts that circulate blood through the body.
answer:

body