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: Flies are insects with two wings. 
Sentence2: Flies are arthropods with two wings.
answer:
Flies


question:
Sentence1: a battery converts chemical energy into electrical energy. 
Sentence2: A battery produces a flow of electrons.
answer:
battery


question:
Sentence1: Amphibians have a relatively complex circulatory system with a three-chambered heart. 
Sentence2: Toads have a relatively complex circulatory system with a three chambered heart.
answer:

circulatory