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: Refraction is the bending of light. 
Sentence2: a rainbow is formed by bending of light by separating light into all different colors.

SOLUTION: bending

PROBLEM: Sentence1: Oil and gasoline are fossil fuels. 
Sentence2: lawn mowers convert fossil fuels into motion.

SOLUTION: fossil

PROBLEM: Sentence1: ink is used for hiding from predators by octopuses. 
Sentence2: Squids and octopuses reproduce sexually.

SOLUTION:
octopuses