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: Most soil nutrients are cations. 
Sentence2: decomposition increases the amount of cations in the soil.

SOLUTION: cations

PROBLEM: Sentence1: An astronaut is a scientist who is a space explorer. 
Sentence2: Space explorers require preserved food for long flights.

SOLUTION: explorer

PROBLEM: Sentence1: force causes the speed of an object to increase. 
Sentence2: force causes the speed of a crystal ball to increase.

SOLUTION:
causes