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: cell division often causes growth. 
Sentence2: Mitosis is cell division.

A: cell
****
Q: Sentence1: Dilation occurs when cell walls relax. 
Sentence2: Decreased oxygen levels cause blood vessels to dilate and cell walls to relax.

A: relax
****
Q: Sentence1: Potassium is a mineral, like calcium . 
Sentence2: potassium is essential for body processes.

A:
Potassium
****