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: All monkeys are mammals. 
Sentence2: monkeys conserve body heat with their hair or fur.
[A]: monkeys


[Q]: Sentence1: Competition may lead to aggressive behaviors or displays of aggression. 
Sentence2: Aggression Aggression and violence often go together.
[A]: aggression


[Q]: Sentence1: if an object is made of a material then that object has the properties of that material. 
Sentence2: Toxicity is an inherent property of the material.
[A]:
material