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: June Summer Triangle Three bright stars light up the summer sky. 
Sentence2: Nuclear reactions in stars cause them to brighten up the summer sky.

SOLUTION: bright

PROBLEM: Sentence1: Pregnancy is the carrying of one or more offspring from fertilization until birth. 
Sentence2: An elephant carries their offspring from fertilization until birth, 22 months later.

SOLUTION: fertilization

PROBLEM: Sentence1: Mutualism is a symbiotic relationship in which both species benefit. 
Sentence2: cucumbers and corn possess a mutualism in which both species benefit.

SOLUTION:
Mutualism