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.

[EX Q]: Sentence1: Heterotrophs get food by eating other living things. 
Sentence2: fish eat other living things.
[EX A]: living

[EX Q]: Sentence1: microbial fuel cells convert chemical energy into electrical energy. 
Sentence2: microbial fuel cells convert chemical energy into kinetic energy.
[EX A]: cells

[EX Q]: Sentence1: a calculator is used for adding. 
Sentence2: arithmetic includes uses for subtraction.
[EX A]:
used