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: Cells are the microscopic building blocks of organisms. 
Sentence2: proteins are the building blocks of organisms.
[A]: organisms


[Q]: Sentence1: All frogs are amphibians. 
Sentence2: frogs have permeable skin that easily absorbs substances from the environment.
[A]: frogs


[Q]: Sentence1: Ascothoracican barnacles attach to echinoderms or corals. 
Sentence2: corals use pheromones to communicate with each other.
[A]:
corals