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.

[EX Q]: Sentence1: If there is enough moisture in the clouds, rain is produced. 
Sentence2: Clouds lacking water reduces rainfall.
[EX A]: clouds

[EX Q]: Sentence1: an animal requires warmth for survival. 
Sentence2: Light and heat and warmth are basic necessities for survival.
[EX A]: warmth

[EX Q]: Sentence1: Clouds are made of water vapor. 
Sentence2: Beads of water can be formed by clouds.
[EX A]:
Clouds