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: Evaporation of sweat uses energy, and the energy comes from body heat. 
Sentence2: Evaporation of sweat uses energy, and the energy comes from exercise.

SOLUTION: Evaporation

PROBLEM: Sentence1: the Earth being tilted on its rotating axis causes seasons. 
Sentence2: the planet's orbit and tilt causes seasons.

SOLUTION: seasons

PROBLEM: Sentence1: Most plants are either insect pollinated or wind pollinated. 
Sentence2: Most plants require either insects or wind.

SOLUTION:
Most