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: Allergens can trigger asthma attacks.
answer:
allergen


question:
Sentence1: exercise increases a body 's strength. 
Sentence2: Exercise is more than running and lifting.
answer:
exercise


question:
Sentence1: temperature changing can cause phase changes. 
Sentence2: temperature changing can cause change of state.
answer:

can