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.
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Question: Sentence1: Faster metabolism means more calories consumed, and usually, weight loss. 
Sentence2: mammals generate heat by consuming calories.

Answer: calories


Question: Sentence1: natural magnetism is used for pointing north by a compass. 
Sentence2: For the ordinary compass, align to the North direction.

Answer: north


Question: Sentence1: Allergies are a reaction of the immune system to harmful particles in the air. 
Sentence2: A breathing mask can prevent an allergic reaction.

Answer:
Allergies