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 Input:
Sentence1: Amphibians have permeable skin that easily absorbs substances from the environment. 
Sentence2: permeable skin easily absorbs air to breathe through.

Ex Output:
absorbs


Ex Input:
Sentence1: Hydrogen bonds cause water to expand when it freezes. 
Sentence2: Hydrogen bonds Hydrogen bonds are primarily electrostatic in origin.

Ex Output:
Hydrogen


Ex Input:
Sentence1: Hormones control many cell activities, so they are very important for homeostasis. 
Sentence2: Illness is an imbalance in homeostasis.

Ex Output:

homeostasis