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: bacteria can cause people to become ill. 
Sentence2: bacteria can cause people to die.
[EX A]: bacteria

[EX Q]: Sentence1: Lymphocytes are the key cells involved in the immune response. 
Sentence2: The key cells involved in the immune response produce antibodies.
[EX A]: cells

[EX Q]: Sentence1: hiding can be used for avoiding predators. 
Sentence2: Camouflage is used for avoiding predators.
[EX A]:
avoiding