TASK DEFINITION: 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.
PROBLEM: Sentence1: Absorption of nutrients occurs mainly in the small intestine. 
Sentence2: The small intestine is the main place where food absorption occurs.

SOLUTION: intestine

PROBLEM: Sentence1: forming coal requires decaying vegetation. 
Sentence2: Forming fossil fuels requires decaying vegetation.

SOLUTION: decaying

PROBLEM: Sentence1: Amphibians have permeable skin that easily absorbs substances from the environment. 
Sentence2: amphibians easily absorb chemicals.

SOLUTION:
Amphibians