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: Hair helps to insulate and protect the body. 
Sentence2: most mammals have insulation that also protects the body.

SOLUTION: body

PROBLEM: Sentence1: All cells share some of the same structures and basic functions. 
Sentence2: Inside the cell is a structure called the nucleus.

SOLUTION: cells

PROBLEM: Sentence1: More trees are cut for firewood and for homes. 
Sentence2: using firewood for homes allows sunlight to become available to the surrounding plants.

SOLUTION:
firewood