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: Precipitation falls on the windward side of the mountain range. 
Sentence2: Mountains have higher precipitation than adjacent lowlands.

SOLUTION: Precipitation

PROBLEM: Sentence1: Hydrogen bonds cause water to expand when it freezes. 
Sentence2: Water freezes into ice when cooled.

SOLUTION: freezes

PROBLEM: Sentence1: X-rays are a form of electromagnetic energy, or radiation. 
Sentence2: Electromagnetic energy is used in medical technology.

SOLUTION:
electromagnetic