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: Soil Erosion Soil erosion is a natural process. 
Sentence2: wind and rain is a natural process.

SOLUTION: natural

PROBLEM: Sentence1: Echinoderms use pheromones to communicate with each other. 
Sentence2: Echinoderms are known for their round symmetry.

SOLUTION: Echinoderms

PROBLEM: Sentence1: Mammals can also generate little bursts of heat by shivering. 
Sentence2: Polar bears are mammals.

SOLUTION:
Mammals

