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: Nitrogen is found in proteins, nucleic acids, and chlorophyll. 
Sentence2: Life without protein is impossible.
[EX A]: proteins

[EX Q]: 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.
[EX A]: our

[EX Q]: Sentence1: Energy used for heating is the single most commonly used form of energy worldwide. 
Sentence2: Heating buildings is a very common production of energy worldwide.
[EX A]:
Energy