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: Organisms cluster around hydrothermal vents in the ocean floor. 
Sentence2: vents on the ocean floor are powered by heat.

SOLUTION: vents

PROBLEM: Sentence1: lightning can cause a forest fire. 
Sentence2: Lightning can cause a natural cycle in forests.

SOLUTION: lightning

PROBLEM: Sentence1: stalactites are formed by deposition. 
Sentence2: Soils are sand, clay, limestone, and organic deposits.

SOLUTION:
deposition