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: Oxygen fatigue is a shortage of oxygen reaching the brain. 
Sentence2: Plants can reduce fatigue during the daytime.

SOLUTION: fatigue

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

SOLUTION: trees

PROBLEM: Sentence1: Weights A measure of the heaviness or mass of an object is the object's weight. 
Sentence2: An item's weight causes its gravitational force.

SOLUTION:
weight