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: keeping food cold is used for keeping food fresh. 
Sentence2: Keeping food at 40 degrees F or lower is used for keeping food fresh.

A: food
****
Q: Sentence1: Flowers produce seeds for reproduction. 
Sentence2: flowers require dispersal for reproduction.

A: Flowers
****
Q: Sentence1: Cells cannot survive without oxygen. 
Sentence2: the basic building blocks of life cannot survive without oxygen.

A:
cannot
****