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: Producers use energy and inorganic molecules to make food. 
Sentence2: Green plants use energy and inorganic molecules to make food.

SOLUTION: energy

PROBLEM: Sentence1: Propane can be either a liquid or a gas. 
Sentence2: heat can be added to propane to change it's properties through the boiling process.

SOLUTION: Propane

PROBLEM: Sentence1: Plants use unsaturated fatty acids to store energy. 
Sentence2: Among the unsaturated fatty acids are compounds with one, two or three double bonds.

SOLUTION:
acids