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.

Q: Sentence1: Blood is a fluid connective tissue. 
Sentence2: A fluid connective tissue carries oxygen to the brain.

A: connective
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Q: Sentence1: the mass of an object causes the gravitational force exerted by that object. 
Sentence2: gravitational force accelerates objects.

A: force
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Q: Sentence1: Energy is passed up a food chain or web from lower to higher trophic levels. 
Sentence2: Each trophic level has less biomass and a loss of energy content.

A:
trophic
****