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: Many corals secrete an exoskeleton that builds up to become a coral reef. 
Sentence2: Corals construct an exoskeleton by secreting calcium  carbonate.

corals