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: looking at bright objects has a negative impact on the eyes. 
Sentence2: Looking at bright objects have a negative impact on the retina.

Answer: bright


Question: Sentence1: Urine leaves the body through a sphincter in the process of urination. 
Sentence2: urine leaves the body upon relaxation of a muscle.

Answer: Urine


Question: Sentence1: Each system is equipped with a control, a heat producer, a heat exchanger, and a heat distributor. 
Sentence2: buildings use a combination of production, exchange, and distribution of energy to regulate temperatures.

Answer:
distributor