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: Balance is the ability to sense and maintain body position. 
Sentence2: Another part of the inner ear is used for balance.

SOLUTION: Balance

PROBLEM: Sentence1: creating paper requires cutting down trees. 
Sentence2: Trees begin as epiphytes on host trees.

SOLUTION: trees

PROBLEM: Sentence1: unequal heating of Earth 's surface by the Sun causes global wind patterns. 
Sentence2: Global wind patterns are caused by unequal absorption of radiation.

SOLUTION:
global