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: harming an animal species causes that animal 's population to decrease. 
Sentence2: Oil spill sare harmful to animals and the enviroment.

SOLUTION: harming

PROBLEM: Sentence1: burning fossil fuels increases the carbon in the atmosphere. 
Sentence2: the byproduct of fossil fuels is carbon.

SOLUTION: carbon

PROBLEM: Sentence1: Carbon cycles quickly between organisms and the atmosphere. 
Sentence2: Deforestation also disrupts the Carbon Cycle.

SOLUTION:
Carbon