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: Boiling water can cause burns. 
Sentence2: heating water can cause burns.
[EX A]: water

[EX Q]: Sentence1: friction causes the temperature of an object to increase. 
Sentence2: Friction causes the temperature of a toy to increase.
[EX A]: causes

[EX Q]: Sentence1: Puppies as well as kittens are curious animals. 
Sentence2: Kittens can learn behavior through play.
[EX A]:
kittens