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: Any antigen that causes an allergy is called an allergen. 
Sentence2: molds are antigens.
answer:
antigen


question:
Sentence1: a battery converts chemical energy into electrical energy. 
Sentence2: Battery electricity comes conversion.
answer:
battery


question:
Sentence1: Many plants respond to the days growing shorter in the fall by going dormant. 
Sentence2: Plants can be moved in the fall.
answer:

fall