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: sharpening an object causes that object to change shape. 
Sentence2: sharpening a knife causes it to change shape.
answer:
causes


question:
Sentence1: Similarly, stars are referred to as suns, but our star is the Sun. 
Sentence2: our star causes water to evaporate more quickly by adding heat.
answer:
our


question:
Sentence1: Chlorophyll gives plants a green color. 
Sentence2: nitrogen is found in what gives plants a green color.
answer:

color