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: Distance is measured in meters the SI unit of distance. 
Sentence2: The SI unit of distance is in meters.

SOLUTION: SI

PROBLEM: Sentence1: Most water comes from precipitation. 
Sentence2: aquatic animals require precipitation to survive.

SOLUTION: precipitation

PROBLEM: Sentence1: Examples of tissues are muscle tissue or nerve tissue. 
Sentence2: muscles contain cells.

SOLUTION:
muscle