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: Runoff water is wasted water. 
Sentence2: Streams may start with wasted water.

Answer: wasted


Question: Sentence1: Complex chemistry is needed to carry out all the functions of life. 
Sentence2: Chemistry is primarily concerned with matter, energy, and their interactions.

Answer: chemistry


Question: Sentence1: All plants require sunlight to make their food. 
Sentence2: A plant requires sunlight for survival.

Answer:
sunlight