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: a plant requires sunlight to grow. 
Sentence2: Grass needs air and sunlight.
answer:
sunlight


question:
Sentence1: gills are used for breathing water by aquatic animals. 
Sentence2: gills are used for breathing water by sharks.
answer:
are


question:
Sentence1: tidal energy can be used to produce electricity. 
Sentence2: Electricity is electrons in motion.
answer:

electricity