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.

Sentence1: Some viruses live in a dormant state inside the body. 
Sentence2: a virus can live in the brain.
viruses

Sentence1: Refrigerators are major users of electricity. 
Sentence2: Keeping food fresh for a long period of time requires a lot of electricity.
electricity

Sentence1: a warm front causes cloudy and rainy weather. 
Sentence2: Stratus clouds are associated with a warm front.

front