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: being burried under soil and mud changes peat into coal through extreme heat and pressure in a swamp over a long period of time. 
Sentence2: Marble is used for sculptures, and coal is used for fuel and energy like light.

SOLUTION: coal

PROBLEM: Sentence1: Light is the visible form of electromagnetic energy. 
Sentence2: Electromagnetic energy enters the eye through an opening called the pupil.

SOLUTION: electromagnetic

PROBLEM: Sentence1: Lung cancer is most often caused by exposure to tobacco smoke. 
Sentence2: Secondhand smoke is also known as Environmental Tobacco Smoke.

SOLUTION:
tobacco