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: Aggression is behavior that is intended to cause harm or pain. 
Sentence2: Verbal violence is behavior that is intended to cause harm or pain.

SOLUTION: behavior

PROBLEM: Sentence1: If there is enough moisture in the clouds, rain is produced. 
Sentence2: Clouds lacking water reduces rainfall.

SOLUTION: clouds

PROBLEM: Sentence1: the mass of an object causes the gravitational force exerted by that object. 
Sentence2: Gravity is the force that keeps the earth in orbit about our sun.

SOLUTION:
force