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: cell division often causes growth. 
Sentence2: Cell division leads to reproduction.

SOLUTION: cell

PROBLEM: Sentence1: Sulfur is a good electrical insulator. 
Sentence2: Sulfur slows the transfer of electricity.

SOLUTION:
Sulfur