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: if an organism becomes too hot then that organism may die. 
Sentence2: a plant can collapse if it gets too hot.

SOLUTION: hot

PROBLEM: Sentence1: Cancer is a disease in which cells divide out of control. 
Sentence2: Cancer is a disease in which cells grow and divide rapidly.

SOLUTION: Cancer

PROBLEM: Sentence1: a cavern is formed by carbonic acid in groundwater seeping through rock and dissolving limestone. 
Sentence2: carbon dioxide in groundwater creates caverns.

SOLUTION:
cavern