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.

Sentence1: All frogs are amphibians. 
Sentence2: frogs have permeable skin that easily absorbs substances from the environment.
frogs

Sentence1: bacteria can cause people to become ill. 
Sentence2: bacteria can cause people to die.
bacteria

Sentence1: skin is used for protecting the body from harmful substances. 
Sentence2: the epidermis and dermis protects the body from harmful substances.

body