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: moss causes chemical weathering. 
Sentence2: Sphagnum moss mixed with peat moss.

Answer: moss


Question: Sentence1: People of all ages and activity levels perspire or sweat. 
Sentence2: Perspiration reduces body heat.

Answer: perspire


Question: Sentence1: when light enters the eye through the pupil , that light falls on the retina. 
Sentence2: Cones are coned shaped cells of the retina that respond to light.

Answer:
retina