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: Plants exhibit phototropism, or growing toward a light source. 
Sentence2: Bamboos are vigorous, rugged plants.

SOLUTION: Plants

PROBLEM: Sentence1: if an animal lives under ground then that animal will be protected from a wild fire. 
Sentence2: Animals living under ground deal with fire remarkably well.

SOLUTION:
animal