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: Most genes contain the instructions for a single protein. 
Sentence2: Most genes contain the instructions for protein destinations.

SOLUTION: Most

PROBLEM: Sentence1: a circle graph can be used to display percents. 
Sentence2: pie charts are circle graphs.

SOLUTION: circle

PROBLEM: Sentence1: riding a bike does not cause pollution. 
Sentence2: Riding a bike will not degrade habitat.

SOLUTION:
bike