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: An example of a cartilaginous fish is a shark. 
Sentence2: jaws make sharks excellent predators.
answer:
shark


question:
Sentence1: Some birds are pollinators that co-evolved with plants. 
Sentence2: insects pollinate plants.
answer:
plants


question:
Sentence1: Nuclear reactions convert mass to energy. 
Sentence2: Stars convert mass to energy.
answer:

convert