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: Most water comes from precipitation. 
Sentence2: aquatic animals require precipitation to survive.
[A]: precipitation


[Q]: Sentence1: Some viruses live in a dormant state inside the body. 
Sentence2: a virus can live in the brain.
[A]: viruses


[Q]: Sentence1: Echinoderms use pheromones to communicate with each other. 
Sentence2: Echinoderms and molluscs use adhesives to grip the substrate during locomotion.
[A]:
use