Definition: 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.
Input: Sentence1: Cells secrete acids and bases to maintain the proper pH for enzymes to work. 
Sentence2: For biological catalysts to be able to work, cells secrete acids and bases to maintain proper pH.

pH