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: Lions live in social groups called prides. 
Sentence2: Chimpanzees live in social groups called communities.
[EX A]: groups

[EX Q]: Sentence1: Instead, the body is covered with a protective shell of bony armor. 
Sentence2: Most mollusks have protective of bony armor.
[EX A]: armor

[EX Q]: Sentence1: Birds have relatively large brains and a high level of intelligence. 
Sentence2: Large brains require large skulls.
[EX A]:
brains