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: a flashlight converts chemical energy into light energy. 
Sentence2: Only as long as there are batteries in the flashlight, the flashlight will function.
[EX A]: flashlight

[EX Q]: Sentence1: To keep cut flowers lasting longer, use a commercial florist preservative such as Floralife. 
Sentence2: Dehydrating food is used to make it last longer.
[EX A]: lasting

[EX Q]: Sentence1: Populations of viruses do not grow through cell division because they are not cells. 
Sentence2: HIV, like other viruses, needs a host to survive.
[EX A]:
viruses