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: Heat is a measurement of transferable energy. 
Sentence2: preventing the transfer of energy from an organism's body causes it to keep warm.
A: 
energy